Methods for performing a non-contact electrical measurement on a cell, chip, wafer, die, or logic block

ABSTRACT

Systems, devices, and methods for performing a non-contact electrical measurement (NCEM) on a NCEM-enabled cell included in a NCEM-enabled cell vehicle may be configured to perform NCEMs while the NCEM-enabled cell vehicle is moving. The movement may be due to vibrations in the system and/or movement of a movable stage on which the NCEM-enabled cell vehicle is positioned. Position information for an electron beam column producing the electron beam performing the NCEMs and/or for the moving stage may be used to align the electron beam with targets on the NCEM-enabled cell vehicle while it is moving.

RELATED APPLICATIONS

This application is a NON-PROVISIONAL patent application of and claimspriority to U.S. Provisional Application No. 62/909,141, filed 1 Oct.2019, and entitled “SYSTEMS, DEVICES, AND METHODS FOR PERFORMING ANON-CONTACT ELECTRICAL MEASUREMENT ON A MOVING CELL, CHIP, WAFER, DIE,OR LOGIC PORTION THEREOF AND SYSTEMS, DEVICES, AND SYSTEMS, DEVICES, ANDMETHODS FOR PERFORMING A COMPARATIVE ANALYSIS BETWEEN DIFFERENT CELLS,CHIPS, DIES, AND/OR LOGIC SECTIONS THEREOF PRESENT ON A WAFER” and is aNON-PROVISIONAL patent application of and claims priority to U.S.Provisional Application No. 62/945,553, filed on 9 Dec. 2019 andentitled “SYSTEMS, DEVICES, AND METHODS FOR PERFORMING A NON-CONTACTELECTRICAL MEASUREMENT ON A CELL, NON-CONTACT ELECTRICAL MEASUREMENTCELL VEHICLE, CHIP, WAFER, DIE, OR LOGIC BLOCK,” both of which areincorporated, in their entireties, by reference herein.

FIELD OF INVENTION

The present invention is directed to systems, devices, and methods forperforming a non-contact electrical measurement (NCEM) on a NCEM-enabledcell included in a NCEM-enabled cell vehicle. At times, the NCEM-enabledcell vehicle may be moving due to its positioning on a moving stage andthe NCEM measurement may be performed while the NCEM-enabled cellvehicle is moving.

BACKGROUND

During a particle beam and/or electron beam inspection process, asemiconductor wafer or a device under test (DUT) may be exposed to aparticle and/or electron beam so that different regions of the wafer/DUTmay be exposed to and/or tested using the particle/electron beam. Oftentimes, the wafer/DUT is positioned on a movable stage configured to movethe wafer/DUT so that different areas of the wafer/DUT may be positionedunder an electron beam column for testing. This movement of the stagemay introduce uncertainty into testing process and, more specifically,may make it difficult to precisely determine a position of the wafer/DUTand/or a portion thereof before, during, and/or after movement of thestage which can cause throughput delays and/or errors in the testingprocess.

SUMMARY

Systems, devices, and methods for performing a non-contact electricalmeasurement (NCEM) on a NCEM-enabled cell included in a NCEM-enabledcell vehicle are herein described. The NCEM-enabled cell vehicle may beany semiconductor device (e.g., wafer, chip, die, memory, memorycomponent, etc.) and an NCEM-enabled cell may be anyelectrically-responsive cell positioned within the NCEM-enabled cellvehicle. The NCEM measurements may be performed using a particle beam,such as an electron beam, that is projected toward a target on theNCEM-enabled cell vehicle. A response of the target to the particle beammay be detected and analyzed to determine, for example, whether thetarget's response to the particle beam is correct and/or indicateswhether the target is operational and/or defective. At times, theNCEM-enabled cell vehicle may be moving underneath the particle beam dueto its positioning on a moving stage to facilitate, for example,incidence of the particle beam on different targets on the NCEM-enabledcell vehicle. At times, the NCEM measurement may be performed while theNCEM-enabled cell vehicle is moving. The movement may be continuouswhile a column or swath of discrete portions of the NCEM-enabled cellvehicle (also referred to herein as “tiles”) is moved under an electronbeam column so that the electron beam may test different tiles.Alternatively, the movement may be variable so that, for example, astage moves incrementally to position a tile so that it is centered, ornearly centered, within an electron beam's point of view. The tile mayremain in this position (or may be slowing moving toward and/or away thecenter of the field of view of the electron beam column) until all testsites (e.g., NCEM-enabled cells) within the tile are exposed to theelectron beam. Then, the stage may move the NCEM-enabled cell vehicle sothat a subsequent tile may be centered within the field of view of theelectron beam column so that it may be exposed to the electron beam.Measurements provided by the systems described herein may be, forexample, voltage contrast measurements and/or images.

In some embodiments, a recipe for an NCEM-enabled cell vehicle, die,NCEM-enabled cell, and/or set of NCEM-enabled cells included in a waferor NCEM-enabled cell vehicle may be received by a processor and/orcomputer. The NCEM-enabled cell vehicle, die, NCEM-enabled cell, and/orset of NCEM-enabled cells may be divided into a plurality of regions, ortiles, and each tile may include a registration area and a plurality ofnon-contact electronic measurement (NCEM)-enabled cells. In someinstances, tile size may be responsive to, for example, a path lengthfor the electron beam column, a size and/or shape of a field of view ofthe electron beam column, and/or a feature of the wafer (e.g., chipsize, arrangement of components, etc.). The recipe may includeinformation (e.g., type, position, dimensions, etc.) regarding, forexample, contents of the tiles, NCEM-enabled cell vehicle, die,NCEM-enabled cell, and/or set of NCEM-enabled cells and/or systemparameters (e.g., beam drift, stage velocity, vibrations in the system,movement parameters for components of the system, etc.) for a systemperforming the NCEM on the NCEM-enabled cell vehicle, die, NCEM-enabledcell, and/or set of NCEM-enabled cells.

An expected position of a registration area included in a tile of theplurality of tiles may then be determined using, for example, therecipe. In some embodiments, the registration area may include aplurality of features (e.g., NCEM-enabled cells, product standard cells,lines, circuits, etc.) and determination of an expected position of theregistration area may include determining an expected position of one ormore of the plurality of features.

An electron beam column may then be instructed to raster scan a regionof the tile corresponding to the expected position of the registrationarea using an electron beam emanating from an electron beam column.

An indication of a response of the region of the tile corresponding tothe expected location of the registration area to the electron beam maythen be received. The indication of a response may be a signal from anelectron detector that has detected electrons emanating from the regionof the tile corresponding to the expected location of the registrationarea (e.g., an electron count and/or grey level), a voltage contrastmeasurement, and/or an image of the region of the tile corresponding tothe expected location of the registration area. In some embodiments, theindication of the response of the NCEM-enabled cell to the alignedelectron beam may be a voltage contrast measurement and/or an image.Additionally, or alternatively, the indication of the response of theNCEM-enabled cell to the aligned electron beam is a detector currentthat indicates a measure of detected electron intensity. In someinstances, the detector current may be converted into a grey level.

The indication of the response and/or image may then be analyzed todetermine an actual position of the registration area by, for example,comparing a position of features of the expected location of theregistration area as indicated by the recipe and a position of featuresof the raster scanned area.

The operation of the electron beam column and/or a deflection of theelectron beam emanating therefrom may then be aligned and/orrecalibrated using the actual position of the registration area. Then,the aligned electron beam may be sequentially directed toward each oftargets (e.g., target NCEM-enabled cells) included in the tile. Aresponse (e.g., an electron count, an image, a voltage contrastmeasurement, a grey level, etc.) of each of the targets to the alignedelectron beam may then be received and an indication of the response maybe provided to a processor.

At times, more than one tile may be tested and/or a response of the tileto an electron beam may be received and this process may be repeated forsome, or all, tiles included in an NCEM-enabled cell vehicle. In someembodiments, a difference between the expected and actual position offor a plurality of scanned registration areas may be determined. Thesedifferences may be used to determine an amount of electron beam drift,or movement of an electron beam column generating the electron beam overtime as successive registration areas are scanned. The electron beamdrift may then be used to align the electron beam when it is directedtoward a subsequent target (e.g., a registration area or an NCEM-enabledcell).

On some occasions, the NCEM-enabled cell vehicle may be positioned on astage that moves while the registration area is exposed to the electronbeam and position information for the stage (and consequently the wafer)as it moves may be received by, for example, the processor or computer.The position information may be received from, for example, positionassessment hardware, an interferometer, and/or an optical encoder. Thedeflection angle of the electron beam may then be adjusted while rasterscanning the registration area so that the raster scanning may beresponsive to and/or correspond with the movement of the stage and/orthe position information for the stage so that the raster scan of theregistration area may be completed while the stage, and consequently thewafer, is moving.

Additionally, or alternatively, position information for an electronbeam column that generates the electron beam may be received along withposition information for the stage as the wafer moves along with themoving stage. A position of the stage relative to the electron beamcolumn may then be determined and a deflection angle of the electronbeam on the registration area may be adjusted while raster scanning theregistration area. The adjustment of the deflection angle may beresponsive to the position of the stage relative to the electron beamcolumn so that the raster scan of the registration area may be completedwhile the wafer is moving to collect a registration image.

In some embodiments, absolute and/or relative position information(e.g., in the X- and/or Y-direction) for the stage and/or electron beamcolumn that generates the electron beam may be received. The positioninformation for the stage and/or electron beam column may be receivedfrom by, for example, an interferometer and/or an optical encoder.Relative position between the stage and the electron beam column maythen be determined using, for example, absolute position information ofthe stage and the electron beam column and/or via analysis of a compoundbeam that is incident on both the stage and electron beam column.

A deflection angle of the electron beam as it exits the electron beamcolumn and is directed toward the registration area may then be adjustedwhile raster scanning the registration area responsively to the relativeposition between the stage and the electron beam column. At times, thewafer may be positioned on a moving stage and the position informationfor the stage and electron beam column may be received over a timeinterval (e.g., a length of time needed to raster scan the registrationarea).

The position of the stage and/or the electron beam column may becontinuously and/or sequentially determined over the time interval usingthe absolute and/or relative position information for the stage and theelectron beam column received over the time interval. The deflectionangle of the electron beam as it exits the electron beam column and isdirected toward the registration area may then be adjusted over the timeinterval while raster scanning the registration area responsively to therelative position between the stage and the electron beam column so thatthe raster scan of the registration area may be completed while thewafer is moving. In some embodiments, the position information may becontinuously and/or periodically (e.g., every 0.1 or 1 microsecond)received while the stage is moving.

In some embodiments, the registration area may include a plurality offeatures like NCEM-enabled cells, NCEM-enabled fill cells, memory cells,and/or product standard cells, and determining the expected position ofthe registration area comprises determining an expected position for twoor more of the plurality of features and determining the actual positionof the registration area comprises determining an actual position forthe two or more features of the plurality of features using the image.In these embodiments, the expected and actual position for each of thetwo or more features of the registration area may be compared with oneanother to, for example, determine a difference therebetween. Thisdifference may be used to, for example, determine an amount of beamdrift and/or align the electron beam.

BRIEF DESCRIPTION OF THE FIGURES

The present invention is illustrated by way of example, and notlimitation, in the figures of the accompanying drawings in which:

FIG. 1A provides a side view of a first exemplary system for testing aNCEM-enabled cell vehicle using a non-contact electronic measurement(NCEM) using a first exemplary type of position assessment, inaccordance with some embodiments of the present invention;

FIG. 1B provides a top view of portions of the first system, inaccordance with some embodiments of the present invention;

FIG. 2A provides a side view of a second exemplary system for testing aNCEM-enabled cell vehicle using a non-contact electronic measurement(NCEM) using a second exemplary type of position assessment, inaccordance with some embodiments of the present invention;

FIG. 2B provides a top view of portions of the second system, inaccordance with some embodiments of the present invention;

FIG. 3A provides a side view of a third exemplary system for testing aNCEM-enabled cell vehicle using a non-contact electronic measurement(NCEM) using a third exemplary type of position assessment, inaccordance with some embodiments of the present invention;

FIG. 3B provides a top view of portions of the third system, inaccordance with some embodiments of the present invention;

FIGS. 4A-4C provide a side views of the system of FIG. 1A while rasterscanning a target with an electron beam while the target is situatedstage that is moving over time, in accordance with some embodiments ofthe present invention;

FIG. 5A provides a block diagram of exemplary tiles included within aNCEM-enabled cell vehicle, in accordance with some embodiments of thepresent invention;

FIG. 5B provides a block diagram of exemplary tiles within a swath, inaccordance with some embodiments of the present invention;

FIG. 5C provides a block diagram of an exemplary logic section that maybe included in a tile that includes a registration area, in accordancewith some embodiments of the present invention;

FIG. 5D provides an outline of exemplary NCEM-enabled fill cells, inaccordance with some embodiments of the present invention;

FIG. 5E provides a block diagram of an exemplary NCEM-enabled fill cell,in accordance with some embodiments of the present invention;

FIG. 6 provides a flowchart illustrating an exemplary process fordetermining an absolute position of a stage, an absolute position of anelectron beam column, and/or a relative position between a stage and anelectron beam column, in accordance with some embodiments of the presentinvention;

FIGS. 7A and 7B provide a flowchart illustrating an exemplary processfor determining an absolute position of a stage, an absolute position ofan electron beam column, and/or a relative position between a stage andan electron beam column, in accordance with some embodiments of thepresent invention;

FIG. 8 provides a flowchart illustrating an exemplary process fordetermining a position of a stage relative to an electron beam column,in accordance with some embodiments of the present invention;

FIGS. 9A and 9B provide a flowchart illustrating an exemplary processfor registering a position of a tile using a registration area andperforming a test on one or more NCEM-enabled fill included within thetile as the tile moves on a stage and is exposed to non-contactelectronic measurement via an electron beam or electron beam, inaccordance with some embodiments of the present invention;

FIGS. 10A and 10B provide a flowchart illustrating an exemplary processfor registering a position of a tile using a registration area andperforming a test on one or more NCEM-enabled fill included within thetile, in accordance with some embodiments of the present invention;

FIG. 11A provides a first image of an expected position of aregistration area where the expected and actual positions of theregistration area align with one another, in accordance with someembodiments of the present invention;

FIG. 11B provides a second image of an expected position of aregistration area where the expected and actual positions of theregistration area do not align with one another, in accordance with someembodiments of the present invention;

FIG. 12A provides a block diagram of an exemplary wafer, in accordancewith some embodiments of the present invention;

FIG. 12B provides an exemplary array of chips, dies, and/or logicportions thereof that are present on a wafer, in accordance with someembodiments of the present invention;

FIG. 13 provides a flowchart illustrating a process for performing acomparative analysis of different dies, chips, and/or logic sectionsthereof for the purpose of error detection, in accordance with someembodiments of the present invention; and

FIG. 14 provides an exemplary graph of pixel grey count for a pluralityof target regions as a function of pixel number, in accordance with someembodiments of the present invention.

Throughout the drawings, the same reference numerals and characters,unless otherwise stated, are used to denote like features, elements,components, or portions of the illustrated embodiments. Moreover, whilethe subject invention will now be described in detail with reference tothe drawings, the description is done in connection with theillustrative embodiments. It is intended that changes and modificationscan be made to the described embodiments without departing from the truescope and spirit of the subject invention as defined by the appendedclaims. Features shown within the drawings are not drawn to scale.

Written Description

The present invention is directed to systems, devices, and methods forperforming a non-contact electrical measurement on a non-contactelectronic measurement (NCEM) enabled cell. An NCEM-enabled cell may beany cell that may respond to a non-contact electronic measurement suchas a voltage contrast measurement. Typically, NCEM-enabled cells have ametal contact by which to conduct the NCEM. Devices that includeNCEM-enabled cells may be any semiconductor device including, notlimited to, a chip, wafer, die, logic block (e.g., a logic portion of achip, wafer, reticle, or die), test chip, a test structure, and/or amemory pad in a memory product. These devices may be collectivelyreferred to herein as a NCEM-enabled cell vehicles. Non-contactelectrical measurements may be performed using a non-contact electricalmeasurement tool that may be a charged particle (electrons or ions)column that projects a beam of charged particles toward an area ofinterest or target (e.g., a registration area and/or a NCEM-enabledcell). An electrical response of an NCEM-enabled cell or group ofNCEM-enabled cells to the charged particle beam may be detected by, forexample, an electron detector, and processed to provide, for example, adetected electron count, a grey level, a voltage contrast measurement,and/or an image of the target. The response may then be used todetermine whether the area of interest is properly operational ordefective.

In some cases, exposure of a cell to a charged particle beam results indestruction of the exposed component. In some embodiments, anNCEM-enabled cell vehicle may include one or more NCEM-enabled fillcells. These NCEM-enabled fill cells may not be configured to perform afunction or otherwise effect an operation of an NCEM-enabled cellvehicle and exposure of the NCEM-enabled fill cells. Because theNCEM-enabled cells do not perform any functions necessary for theoperation of the a NCEM-enabled cell vehicle, exposure of theseNCEM-enabled cells to a charged particle beam, and the damage theseNCEM-enabled cells will suffer as a result, may not adversely impact theoperation of the NCEM-enabled cell vehicle that is being tested usingnon-contact electrical measurements. Thus, in some cases, a NCEM-enabledcell vehicle may be tested using NCEM-enabled fill cells withoutimpacting other components of a NCEM-enabled cell vehicle. Thus,NCEM-enabled cell vehicles may be still be operable following a NCEMtesting process as described herein. This may achieve a reduction inyield loss caused by inspection of NCEM-enabled cell vehicles usingnon-contact electronic measurements.

During testing, the NCEM-enabled cell vehicle may be affixed to a stagethat may be configured to move to facilitate, for example, exposure ofdifferent regions of and/or targets within the NCEM-enabled cell vehicleto the non-contact electrical measurement as part of, for example, aninspection and/or error analysis process. The movement of the stage maybe in any appropriate direction (e.g., X-direction and/or Y-direction)and may be of a continuous and/or varying speed.

In embodiments where movement of the stage is continuous along a row orcolumn of sequentially arranged portions of a NCEM-enabled cell vehicle(a portion of an NCEM-enabled cell vehicle is sometimes referred toherein as a “tile”), the systems, devices, and methods disclosed hereinmay compensate for the continuously moving stage by adjusting adeflection angle and/or direction of a charged particle beam when itexits the particle beam column responsively to the continuous movementof the stage. In this way, targets may be exposed to the chargedparticle beam on the fly as they move along with the stage without theneed to slow or stop the motion of the stage. This may result is anincrease in throughput and/or the speed with which chips, wafers, dies,or logic portions thereof may be tested using NCEMs.

Additionally, or alternatively, in some cases, movement of the stage maynot be continuous along a row or column of sequentially arranged tiles.For example, the stage may move relatively quickly between targetregions but may move slowly as a target region is approached and/or maycome to a complete stop when a target region is correctly positionedbeneath the charged particle beam column. In these cases, movement ofthe stage as it decelerates upon approaching a target and/or accelerateswhen moving from a first target to a second target may be compensatedfor by adjusting a deflection angle and/or direction of a chargedparticle beam when it exits the particle beam column responsively to themovement (or lack thereof) of the stage.

Information regarding a position of the stage and/or movement of thestage may be provided by position assessment hardware that may providean absolute position for the stage and/or particle beam column at anypoint in time and/or continuously. Additionally, or alternatively, theposition assessment hardware may provide a position for the stagerelative to the charged particle beam column at any point in time and/orcontinuously.

Turning now to the figures, FIG. 1A provides a side view of a firstexemplary system 100 for testing a NCEM-enabled cell vehicle using anon-contact electronic measurement (NCEM) using a first exemplary typeof position assessment and FIG. 1B provides a top view of portions ofthe first exemplary system 100.

System 100 includes an electron beam column 120, aserver/computer/processor 110, position assessment hardware (which mayinclude one or more lasers (not shown)) 115, a database 105, a columnfield programmable gate array (FPGA) 107, a position assessment FPGA109, a communication interface 125, a NCEM-enabled cell vehicle 130, anda stage 135 that includes a first mirrored surface 150 (also referred toherein as “first stage mirror 150”) and a second stage mirror 170 (alsoreferred to herein as “second stage mirror 170”).

NCEM-enabled cell vehicle 130 may be any semiconductor device that istested using a particle beam column like an electron beam column 120.Examples of NCEM-enabled cell vehicles 130 include, but are not limitedto a, chip, wafer, die, logic block (e.g., a logic portion of a chip,wafer, reticle, or die), test chip, test structure, and/or memory pad ina memory product. In some embodiments, NCEM-enabled cell vehicle 130 isa wafer, an example of which is shown in FIG. 12A and discussed below.Often times, NCEM-enabled cell vehicle 130 is divided into one or moresections, or tiles, and each tile may include, for example, one or moreregistration areas, test cells, NCEM-enabled cells, NCEM-enabled fillcells, and/or product standard cells. More information aboutregistration areas, product standard cells, NCEM-enabled fill cells, andNCEM-enabled cells is provided herein and, in particular, with regard todiscussions of FIGS. 5A-5E below.

Electron beam column 120 includes, among other features, an electronbeam source 121, a first detector 124A, a second detector 124B, and aset 123 of deflectors 122A, 122B, 122C, and 122D. Electron beam source121 may be configured to generate an electron beam 140 that may bedirected toward an area of interest on NCEM-enabled cell vehicle 130(e.g., a target 185). Exemplary targets include, but are not limited to,a cell, a device under test (DUT), a registration area, an NCEM-enabledcell, and/or an NCEM-enabled fill cell on/in the NCEM-enabled cellvehicle 130. Electron beam source 121 may receive instructions fromcolumn FPGA 107 regarding how and/or when to emit electron beam 140.

Set of deflectors 123 may cooperatively deflect electron beam 140 alongits path through electron beam column 120 so that it is incident on atarget 185 in NCEM-enabled cell vehicle 130 while, for example, stage135 and therefore, NCEM-enabled cell vehicle 130/target 185 is stilland/or is actively or passively (e.g., vibrations) moving. One or moredeflectors 122A, 122B, 122C, and/or 122D may receive instructions fromcolumn FPGA 107 and/or server/computer/processor 110 regarding howand/or when to deflect electron beam 140 by, for example, adjusting adeflection angle Ø of electron beam 140 over time as an area of interestof NCEM-enabled cell vehicle 130 (e.g., target 185) is scanned withelectron beam 140.

Electron detectors 124A and 124B may be configured to detect electronsemanating from NCEM-enabled cell vehicle 130 and/or target 185 that areresultant from an interaction between electron beam 140 and target 185.Detected electrons may form a detected electron signal 145 that mayinclude, for example, secondary electrons, back-scattered electrons, ora combination thereof. Analysis of detected electron signal 145 by, forexample, server, computer, processor 110 may be used to determinewhether, for example, certain features of the NCEM-enabled cell vehicle130 in which target 185 is resident are defective or operable via, forexample, voltage contrast analysis and/or analysis of an image generatedusing detected electron signal 145. Exemplary images that may begenerated using detected electron signal 145 are provided in images 1101and 1102 discussed below with regard to FIGS. 11A and 11B, respectively.

In some cases, detected electron signal 145 may be a detected currentthat may, at times, correspond to detected electron intensity, detectedelectron power, and/or detected electron energy level. In someinstances, these values may be determined for a particular geographicregion of target 185, which may be referred to herein as a pixel. Thedetected current and/or detected electron intensity may be convertedinto a pixel energy level, and/or a grey level by, for example,server/computer/processor 110. In some cases, the detected current,pixel energy level, and/or grey level may be and/or may correspond to avoltage contrast measurement. An exemplary graph 1400 of analysis ofdetected electron signal 145 information for different targets 185 isprovided in FIG. 14 and discussed below.

Stage 135 may be any stage, or movable platform, configured to acceptpositioning of NCEM-enabled cell vehicle 130 thereon and configured tomove in the X- and/or Y-direction(s) so that NCEM-enabled cell vehicle130 and target(s) 185 included therein may be exposed to electron beam140 for the purposes of, for example, measuring a voltage contrastand/or imaging NCEM-enabled cell vehicle 130 as discussed herein.

Stage 135 may include one or more mirrored surfaces such as first statemirror 150 and second stage mirror 170. In many embodiments, firstand/or second stage mirrors 150 and/or 170 are positioned on the sidesof stage 135 and not a portion of stage 135 (e.g., a top) that supportsNCEM-enabled cell vehicle 130. First and second stage mirrors 150 and170 may be arranged and configured to reflect light or otherelectromagnetic radiation incident thereon that, for the sake ofbrevity, may be collectively referred to as “light.” A reflection oflight incident on first stage mirror 150 may be used to determine aposition of stage 135 in a first dimension (e.g., along an X-axis) and areflection of light incident on second stage mirror 170 may be used todetermine a position of stage 135 in a second dimension (e.g., along aY-axis). FIGS. 1A and 1B illustrate an exemplary way light may beincident upon first stage mirror 150 and second stage mirror 170.

Position assessment hardware 115 may be any tool, or combination oftools, configured to acquire and/or determine a position of, and/ormovement information for, stage 135 in the X-, Y-, and/or Z-directionswith a high level of precision (e.g., 1 μm-0.01 nm) and accuracy. Theposition of, and/or movement information for stage 135, may beextrapolated to NCEM-enabled cell vehicle 130 (and therefore target 185)positioned on, or otherwise affixed to, stage 135 because a position ofNCEM-enabled cell vehicle 130 corresponds to the position of stage 135.In some cases, position assessment hardware 115 is and/or includes aninterferometer and/or an optical encoder.

In some embodiments, position assessment hardware 115 produces and/orgathers position and/or motion information for stage 135 by directing afirst beam 155 and/or a second beam 160 of electromagnetic radiation(e.g., visible light, infra-red light, and/or radio waves) toward firststage mirror 150 and/or second stage mirror 170, respectively, of stage135. Characteristics of a reflection of these first and second beams 155and 160 may then be determined by, for example, photodetectors, positionassessment hardware 115, and/or server/computer/processor 110 and usedto determine a position of stage 135 at any given point in time. Morespecifically, position assessment hardware 115 may project first beam155 toward a first mirror 165A, which may be a partially reflectingand/or a half-silvered mirror arranged and configured to split firstbeam 155 into a first reference beam 155R and a first measurement beam155M. First reference beam 155R may be incident on a first photodetector116 and first measurement beam 155M may be incident upon first stagemirror 150. A first reflected beam 156 may be reflected by first stagemirror 150 toward first mirror 165A which may direct first reflectedbeam 157 toward a first flat mirror 166A that may reflect firstreflected beam 157 toward the first photodetector 116. Firstphotodetector 116 may convert first reflected beam 157 and firstreference beam 155R into a digital signal which may then be communicatedto position assessment hardware 115, position assessment FPGA 109,and/or server/computer/processor 110, which may compare first reflectedbeam 157 and first reference beam 155R with one another and determine aposition of stage 135 in a first direction (e.g., the X-direction) usingthe comparison using, for example, a comparison of the phase for firstreference beam 155R and first reflected beam 157 and/or interferometrytechniques.

As seen in FIG. 1B, position assessment hardware 115 projects secondbeam 160 toward a second mirror 165B, which may be a partiallyreflecting and/or half-silvered mirror arranged and configured to splitsecond beam 160 into a second reference beam 160R and a secondmeasurement beam 160M. Second reference beam 160R may be incident on asecond photodetector 117 and second measurement beam 160M may beincident upon second stage mirror 170. A second reflected beam 176 maybe reflected by second stage mirror 170 toward second mirror 165B whichmay direct a portion of second reflected beam 176 toward a second flatmirror 166B. Second flat mirror 166B may reflect second reflected beam176 toward the second photodetector 117. Second photodetector 117 mayconvert second reflected beam 176 and second reference beam 155R into adigital signal which may then be communicated to position assessmenthardware 115, position assessment FPGA 109, and/orserver/computer/processor 110, which may compare second reflected beam176 and second reference beam 160R with one another and determine aposition of stage 135 in a second direction (e.g., the Y-direction)using the comparison by, for example, comparing the phase for secondreference beam 160R and second reflected beam 176 and/or usinginterferometry techniques.

Optionally, a position of electron beam column 120 may be determined inthe first direction (e.g., the X-direction) and/or the second direction(e.g., the Y-direction) by using hardware and/or a process similar tothat used to determine the position of stage 135. For example, positionassessment hardware 115 may project a third beam 175 toward a thirdmirror 165C, which may be a partially reflecting and/or a half-silveredmirror configured to split third beam 175 into a third reference beam175R and a third measurement beam 175M. Third reference beam 175R may beincident on a third photodetector 118 and third measurement beam 175Mmay be incident upon third mirror 180 positioned on an exterior surfaceof electron beam column 120 and a third reflected beam 177 may bereflected by third mirror 180 toward third mirror 165C, which may directa portion of third reflected beam 177 toward a third flat mirror 166C.Third flat mirror 166C may reflect third reflected beam 177 toward thethird photodetector 118. Third photodetector 118 may convert thirdreflected beam 177 and third reference beam 175R into a digital signalwhich may then be communicated to position assessment hardware 115,position assessment FPGA 109, and/or server/computer/processor 110,which may compare third reflected beam 177 and third reference beam 175Rwith one another and determine a position of electron beam column 120 inthe first direction using the comparison.

Position assessment hardware 115 may project a fourth beam 178 toward afourth mirror 165D, which may be a partially reflecting and/or ahalf-silvered mirror configured to split fourth beam 178 into a fourthreference beam 178R and a fourth measurement beam 178M. Fourth referencebeam 178R may be incident on a fourth photodetector 119 and fourthmeasurement beam 178M may be incident upon fourth mirror 180 positionedon an exterior surface of electron beam column 120 and a fourthreflected beam 179 may be reflected by fourth mirror 180 toward fourthmirror 165D, which may direct a portion of fourth reflected beam 179toward a fourth flat mirror 166C. Fourth flat mirror 166C may reflectfourth reflected beam 179 toward the fourth photodetector 119. Fourthphotodetector 119 may convert fourth reflected beam 179 and fourthreference beam 178R into a digital signal which may then be communicatedto position assessment hardware 115, position assessment FPGA 109,and/or server/computer/processor 110, which may compare fourth reflectedbeam 179 and fourth reference beam 178R with one another and determine aposition of electron beam column 120 in the first direction using thecomparison.

In some embodiments, the signals received by first, second, third,and/or fourth detectors 116, 117, 118, and/or 119 may be used todetermine an absolute position of electron beam column 120 and/or stage135, a relative position between electron beam column 120 and stage 135,and/or a relative rate of motion between electron beam column 120 andstage 135 in the X-, Y-, and/or Z-directions. First beam 155, secondbeam 160, third beam 175, and/or fourth beam 178 may be monochromatic asmay be emitted by a laser and/or a combination of wavelengths ofelectromagnetic radiation by emitted by a source present in positionassessment hardware 115. It should be noted that the optical array shownin FIGS. 1A and 1B are exemplary arrangements of mirrors and theposition hardware assessment tool. Other arrangements for directinglight toward first and second stage mirrors 150 and 170 as well asthird, and/or fourth mirrors 180, and/or 181, respectively may also beused.

In some embodiments, information from the first, second, third, and/orfourth detectors 116, 117, 118 and/or 119 may be communicated toserver/computer/processor 110 and/or position assessment FPGA 109 todetermine an absolute position of stage 135, a position of electron beamcolumn 120, and/or a position of stage 135 relative to the electron beamcolumn 120. When the information is communicated toserver/computer/processor 110, server/computer/processor 110 maydetermine the position of stage 135, a position of electron beam column120, and/or a position of stage 135 relative to the electron beam column120 and then provide instructions to column FPGA 107 to adjust theoperation of one more deflectors to, for example, direct electron beam140 toward target 185 as stage 135 moves.

Database 105 may be configured to store instructions for the operationof one more components of the systems described herein and/or executionof one or more processes described herein. In some instances, database105 may be and/or include a vector database that stores vectorcoordinates for features included in one or more different NCEM-enabledcell vehicles 130 or types of NCEM-enabled cell vehicles 130 as, forexample, a recipe for the NCEM-enabled cell vehicles 130. Additionally,or alternatively, database 105 may be configured to store recipes forone or more different NCEM-enabled cell vehicles 130. A recipe mayinclude information regarding features (e.g., registration areas,NCEM-enabled cells, NCEM-enabled fill cells, and/or product standardcells) included in a NCEM-enabled cell vehicle 130 such as theirrespective configurations and/or positions. Additionally, oralternatively, database 105 may be configured to store parameters forone more components of system 100, 200, and/or 300. Exemplary parametersinclude, but are not limited to, rates of motion for stage 135, rates ofacceleration for stage 135, typical vibrational movement for stage 135,NCEM-enabled cell vehicle 130, and/or electron beam column 120, beamdrift for electron beam column, and/or response times for one morecomponents of system 100, 200, and/or 300 when executing instructions.

Column FPGA 107 may be configured to control an operation of, and/orreceive information from, electron beam column 120 and/or featuresresident therein. For example, column FPGA 107 may be configured toalign or adjust an operation of one or more deflector(s) 122A, 122B,122C, and/or 122D in order to, for example, properly direct electronbeam 140 toward target 185. Column FPGA 107 may also be configured toreceive information from one or more detector(s) 124A and/or 124B andcommunicate this information to server/computer/processor 110.

Server/computer/processor 110 may be configured to provide instructionsfor controlling the operation of one or more features of system(s) 100,200, and/or 300 and/or receive information from one or more componentsof system(s) 100, 200, and/or 300. For example,server/computer/processor 110 may be configured to receive informationfrom, and/or provide information to, column FPGA 107, stage 135,position assessment hardware 115, communication interface 125, and/ordatabase 105 to, for example, control an operation thereof.Server/computer/processor 110 may also be configured to receive positioninformation from position assessment hardware 115 and/or photodetectors116, 117, 118, and/or 119 and, in some cases, may be configured tocontrol the operation of column FPGA 107, stage 135, electron beamcolumn 120, and/or deflector 122 responsively to the received positioninformation.

Server/computer/processor 110 may also be configured to execute one ormore steps of the processes described herein using, for example,instructions stored therein and/or in database 105.Server/computer/processor 110 may also be configured to receiveinformation from and/or provide information to communication interface125 such as one or more results of executing one or more of theprocesses disclosed herein.

Communication interface 125 may be any interface (e.g., keyboard,optical scanner, touch screen, mouse, display device, radio frequencyidentification equipment, etc.) configured to receive information from,for example, a user and/or equipment (e.g., a robot). For example,NCEM-enabled cell vehicle 130 may be associated with an identifier(e.g., lot number, manufacturing origin, testing routine, design ofexperiment, etc.) in the form of an optical bar code or RFID tag, whichmay be presented to communication interface 125 for the purposes ofidentifying NCEM-enabled cell vehicle 130 by a user and/or automatedprocess. The NCEM-enabled cell vehicle 130 identifier may then becommunicated to server/computer/processor 110 and used byserver/computer/processor 110 to query database 105 for informationpertaining to the NCEM-enabled cell vehicle 130 such as a recipe offeatures included in NCEM-enabled cell vehicle 130, coordinates offeatures of NCEM-enabled cell vehicle 130, and/or vector coordinates offeatures included in NCEM-enabled cell vehicle 130.

FIG. 2A provides a side view of a second exemplary system 200 fortesting a NCEM-enabled cell vehicle 130 using a non-contact electronicmeasurement (NCEM) that uses a second exemplary type of positionassessment hardware 115 and FIG. 2B provides a top view of portions ofsecond system 200. FIGS. 2A and 2B also show beam paths for light thatis incident upon first stage mirror 150, second stage mirror 170, thirdmirror 180 and fourth mirror 181. An exemplary process 700 for using thesecond exemplary type of position assessment and determining a positionof stage 135 and/or electron beam column 120 using information obtainedby executing the second exemplary type of position assessment isdiscussed below with regard to FIG. 7.

As shown in FIGS. 2A and 2B, an incident first path length beam 210 imay be emitted from position assessment hardware 115 and/or a lightsource (e.g., laser) resident therein and directed toward first stagemirror 150. Incident first path length beam 210 i may then reflect offfirst stage mirror 150 as reflected first path length beam 210 r. Firstreflected first path length beam 210 r may be detected by positionassessment hardware 115 after reflecting from first stage mirror 150. Atime between emission of incident first path length beam 210 i andreceipt of reflected first path length beam 210 r by position assessmenthardware 115 may be used to determine a position of stage 135 in a firstdimension (e.g., the X-direction) according to, for example, process700.

As shown in FIG. 2B, a path of a second path length beam signal 215 maybe emission of incident second path length beam 215 i from positionassessment hardware 115, impingement on second stage mirror 170, andreflection of a reflected second path length beam 215 r from secondstage mirror 170 back to position assessment hardware 115 where it isdetected by a detector therein. A time between emission of second pathlength beam 215 i and receipt of reflected second path length beam 215 rby position assessment hardware 115 may be used to determine a positionof stage 135 in a second dimension (e.g., the Y-direction) according to,for example, process 700.

Optionally, as shown in FIGS. 2A and 2B, a path of a third path lengthbeam 220 may be emission of an incident third path length signal 220 ifrom position assessment hardware, impingement on third mirror 180, andreflection of a reflected third path length beam 220 r from third mirror180 back to position assessment hardware 115 where it is detected by adetector therein. A time between emission of third path length beam 220i and receipt of reflected third path length beam 220 r by positionassessment hardware 115 may be used to determine a position of electronbeam column 120 in a first dimension (e.g., the X-direction) accordingto, for example, process 700.

Optionally, as shown in FIG. 2B, a path of a fourth path length beam 230may be emission of an incident fourth path length beam 230 i fromposition assessment hardware toward fourth mirror 181 and reflection ofa reflected fourth path length beam 230 r from fourth mirror 181 back toposition assessment hardware 115 where it is detected by a detectortherein. A time between emission of fourth path length beam 230 i andreceipt of reflected fourth path length beam 230 r by positionassessment hardware 115 may be used to determine a position of electronbeam column 120 in a second dimension (e.g., the Y-direction) accordingto, for example, process 700.

FIG. 3A provides a side view of a third exemplary system 300 for testinga NCEM-enabled cell vehicle 130 using a non-contact electronicmeasurement (NCEM) using a third exemplary type of position assessmentand FIG. 3B provides a top view of portions of third system 300. Anexemplary process 800 for using the third exemplary type of positionassessment and determining a position of stage 135 and/or electron beamcolumn 120 using information obtained by executing the third exemplarytype of position assessment is discussed below with regard to FIG. 8.

The third exemplary type of position assessment determines a relativeposition between stage 135 and electron beam column 120 by using a firstcompound beam 310 and a second compound beam 320 that are incident onmirrors of both stage 135 and electron beam column 120. As shown inFIGS. 3A and 3B, a relative position between the stage 135 and electronbeam column 120 in a first direction (e.g., the X-direction) may bedetermined by projecting a first compound beam 310 toward third mirror180. A first reflection of first compound beam 311 may be incident upona first reflection mirror 340, which may reflect a second reflection offirst compound beam 312 toward a second reflection mirror 345, which mayreflect a third reflection of first compound beam 313 toward first stagemirror 150. A fourth reflection of first compound beam 314 may then bereflected back to position assessment hardware 115 where it may bedetected by a detector therein. Another exemplary path of the firstcompound beam 310, which is not shown in FIG. 3A or 3B, is a reverse ofthe path shown in FIGS. 3A and 3B, where first compound beam is emittedfrom position assessment hardware 115, is incident on first stage mirror150, reflects to second reflection mirror 345, reflects to firstreflection mirror 340, reflects to third mirror 180, and then reflectsback to position assessment hardware where it is detected by a detectortherein.

FIG. 3B also shows the path of first compound beam 310 and also showsthe path of a second compound beam 320 so that a relative positionbetween the stage 135 and electron beam column 120 in a second direction(e.g., the Y-direction) may be determined. As shown in FIG. 3B, a firstportion of second compound beam 320 is projected toward fourth mirror181. A first reflection of second compound beam 321 may be incident upona third reflection mirror 350, which may reflect a second reflection ofsecond compound beam 322 toward a fourth reflection mirror 355, whichmay reflect a third reflection of second compound beam 323 toward secondstage mirror 170. A fourth reflection of second compound beam 324 maythen be reflected back to position assessment hardware 115 where it maybe detected by a detector therein. Another exemplary path of the secondcompound beam 320, which is not shown in FIG. 3A or 3B, is a reversepath where second compound beam 320 is emitted from position assessmenthardware 115, is incident on second stage mirror 170, reflects to fourthreflection mirror 355, reflects to third reflection mirror 350, reflectsto fourth mirror 181, and then reflects back to position assessmenthardware where it is detected by a detector therein.

FIGS. 4A-4C provide a side view of a portion of system 100, 200, or 300as stage 135 moves, from right to left, over a time interval betweent₁-t₃ and electron beam 140 scans (e.g., raster scan and/or scanning onepoint at a time, which is sometimes referred to as “step and scan”)target 185 of the NCEM-enabled cell vehicle 130 during the timeinterval. A position of stage 135 and/or electron beam column 120 may bedetermined using the first, second, and/or third exemplary types ofposition assessment systems 100, 200, and/or 300 respectively, which areshown in FIGS. 1A/1B, 2A/2B, and 3A/3B, respectively and discussed withregard to process 600, 700, and 800, below and as shown in FIGS. 6, 7,and 8, respectively. The hardware and light beams needed to assess aposition of stage 135 and/or electron beam column 120 is not shown inFIGS. 4A-4C to improve the clarity of the figures. A duration ofinterval t₁-t₃ may be sufficient to, for example, adequately rasterscan, and/or perform a voltage contrast measurement of, target 185 anddetect electrons emanating therefrom as detected electron signal 145.During the scanning, electron beam 140 stays focused on, and/or directedtoward, target area 185 while stage 135 moves so that the entirety (ornearly the entirety) of target 185 is scanned and/or all (or most)targets 185 are scanned as stage 135 continues to move over time (i.e.,over time interval t₁-t₃). Maintaining the focus of electron beam 140 ontarget 185 may be achieved by changing a direction of electron beam 140(e.g., a deflection angle Ø of electron beam 140 exiting electron beamcolumn 120) over time using, for example, one or more of deflector(s)122A, 122B, 122C, and/or 122D so that electron beam 140 remains incidenton target 185 during time interval t₁-t₃.

For the purposes of illustration, FIG. 4A shows a position of stage 135at a first point in time (t₁) where bean 140 exits electron beam column121 with a first deflection angle θt₁ and is incident upon target 185.An exemplary range for first deflection angle θt₁ is 272-270 degreesrelative to an X and Y axis of electron beam column 120 where the Y-axisof electron beam column runs vertically through a center of electronbeam column 120 and the X-axis is parallel to a lower edge of electronbeam column 120 and stage 135. As shown in FIG. 4A, electron signal 145is detected by detector 124B. However, it will be understood that aportion of electron signal 145 may also be detected by detector 124A. Asstage 135 moves to the left at t₂ electron beam 140 is incident upontarget 185 with a second deflection angle θt₂ that decreases inmagnitude relative to deflection angle θt₁. An exemplary range forsecond deflection angle θt₂ is 271-269 degrees relative to the X and Yaxis of electron beam column 120. As shown in FIG. 4B, electron signal145 is detected by detector 124B. However, it will be understood that aportion of electron signal 145 may also be detected by detector 124A. Asstage 135 moves further to the left at t₃ electron beam 140 is directedtoward target 185 with a third deflection angle θt₃ that is smaller inmagnitude than θt₂. An exemplary range for θt₃ is 268-266 degreesrelative to the X and Y axis of electron beam column 120. As shown inFIG. 4C, electron signal 145 is detected by detector 124A. However, itwill be understood that portion of electron signal 145 may also bedetected by detector 124B.

It is noted that the dimensions shown in FIGS. 4A-4C are not drawn toscale and that, in some embodiments, a difference in deflection angle θbetween t1 and t3 may be very small (e.g., 0.0001-0.1 degrees). Anexemplary speed of stage 135 is between 100 microns-100 mm per secondand an exemplary period of time needed to sufficiently scan target 185is 90 nanoseconds-50 microseconds. If, for example, a speed of stage 135is 5 mm per second and the time needed to test target 185 is 3microseconds, a distance that the stage has moved is very small (i.e.,15 nm). Thus, only a small deflection of beam 140 (e.g., a fraction of adegree) may be necessary to scan target 185 while it is moving alongwith stage 135.

FIG. 5A shows a portion of NCEM-enabled cell vehicle 130 divided into anexemplary array of tiles 515 arranged in columns, or swaths, 518.Although shown as vertical columns, a swath 518 may also be a horizontalrow. The number of tiles 515 and the size/proportions of the respectivetiles 515 of FIG. 5A are not drawn to scale. In many instances,dimensions of a tile are uniform over a NCEM-enabled cell vehicle 130,but this need not always be the case. Exemplary dimensions for a tile515 range from 35-65 μm along the length and width. In many cases, tiles515 are square but, this need not always be the case.

Often times, a tile 515 may have one or more NCEM-enabled cells, aplurality of product standard cells, and at least one registration area.In some embodiments, a tile 515 may also include one or moreNCEM-enabled fill cells. In some embodiments, features and/or contentsof tiles 515 and/or swaths 518 may be uniform (or may be intended to beuniform, with the exception of defects) across an NCEM-enabled cellvehicle 130. In other embodiments, features and/or contents of differenttiles 515 and/or swaths 518 may vary (e.g., have different designs orfunctions) across an NCEM-enabled cell vehicle 130. Informationregarding the contents and/or features of the tiles 515 and/or swaths518 within an NCEM-enabled cell vehicle 130 may be referred to herein asa recipe.

When a NCEM-enabled cell vehicle 130 is subjected to non-contactelectrical measurements, or testing, via exposure to a particle beamlike electron beam 140, a stage, like stage 135, on which NCEM-enabledcell vehicle 130 is positioned may move NCEM-enabled cell vehicle 130 sothat each tile 515 in a swath 518 is, for example, sequentially tested.When an end of a first swath 518 is reached, the stage may be configuredto move NCEM-enabled cell vehicle 130 so that a second and, in manycases, adjacent swath 518 of tiles 515 may be subjected to non-contactelectrical measurements. For example, when swaths 518 are verticallyoriented as shown in FIG. 5A, the stage may move NCEM-enabled cellvehicle 130 in the Y-direction until the last tile 515 in the swath 518is reached. Then, the stage may move in the X- and/or Y-direction(s) byan increment sufficient to align the particle and/or electron beam withthe next swath 518 to be exposed to the NCEM so that the next swath 518may be tested.

FIG. 5B provides a block diagram of two exemplary tiles 515A and 515Bincluded within a swath like swath 518. Each of tile 515A and 515Bincludes a registration area 520A and 520B (respectively) and aplurality of target NCEM-enabled cells that are shown in FIG. 5B asfilled-in circles, or dots, that are shown in exemplary positionsthrough tile 515A and 515B. It will be understood that any number ofNCEM-enabled cells may be resident within a tile 515 and that they maybe situated at positions other than what is shown in FIG. 5B. Forexample, when NCEM-enabled cell vehicle 130 is a test chip or testwafer, a density of cells may be much greater than what is shown in FIG.5B. In addition, although only one registration area 520 is shown intile 515, a tile may have a plurality of registration areas 520.

A registration area 520 may be an area of a tile 515 that is scannedand/or imaged for the purpose of determining a precise position of thetile and/or features of the tile. A registration area 520 may haveexemplary dimensions ranging in size from 1-5 μm and may besquarely-shaped or rectangularly-shaped although this need notnecessarily be the case. Registration area 520 may include one or moreNCEM-enabled cells, NCEM-enabled fill cells, and/or product standardcells and may be positioned anywhere within a tile.

In some embodiments, a registration area 520 may include features thatare relatively easy to discern when imaged and/or exposed to an NCEM as,for example, a distinct object (e.g., dark or light square, rectangleand/or line) and/or pattern (e.g., a set of dark lines, a set of darkrectangles, a set of dark lines and rectangles) when a response of thearea 520 is detected and, for example, converted into an image. Visualdistinctiveness of features within an image of a registration are 520may aid in the identification of these features within a scanned areathat is supposed to correspond to the registration area. A positionand/or relative position of these easily discernable features may thenbe determined via analysis of the detected electrons, voltage contrastmeasurement, and/or an image as discussed below.

Each tile 515A and 515B may have an exact center point 524A and 524B,respectively, where a dimension of the tile in the X- and Y-directionsis precisely 0.5, or one half, of the respective width and height (i.e.,displacement in the X- and Y-directions) as shown in FIG. 5B. Each tile515A and 515B may also have a settling window 522A and 522B,respectively, that is in an approximate center of tile 515 that extendsfrom exact center point 524A and 524B, respectively, in the X- andY-directions by, for example, a percentage (e.g., 0.001-2%) of thelength and/or width of the tile or a set distance within a range of0.01-1 μm, with approximately 0.5 μm being common for many systems likesystem 100, 200, and/or 300. In some embodiments, a size and/ordimension of settling window 522 may be responsive to a precision and/orrange of motion of electron beam column 120, stage 135, and/or positionassessment tool 115.

When tiles 515A and 515B are sequentially scanned, a stage like stage135 may move in the Y-direction from a position of 0 toward an positionof 25 micrometers at a relatively fast velocity of, for example, 0.013m/s and then may decelerate to a velocity of approximately 0.0001 m/supon approaching a position corresponding settling window 524A untiltile 515A is precisely positioned within the field of view of theelectron beam column (e.g., exact center point 524A aligns with thecenter of the field of view of the electron beam column). When settlingwindow 522A is within the center of the field of view of the electronbeam column and/or when the velocity of the stage has slowed to below athreshold value (e.g., approximately 0.0001 m/s), raster scanning ofregistration area 520A and the NCEM-enabled cells of first tile 515A maycommence and/or proceed as described herein. Once all of theNCEM-enabled cells of first tile 515A are scanned or otherwise exposedto the electron beam (while the stage is slowly moving to a stopcorresponding to settling window 522A and/or when stopped), the stagemay move so that second tile 515B is positioned within the field of viewof the electron beam column. This motion may involve accelerating thestage so that it moves approximately 50 micrometers in the Y-directionto the settling window 522B of second tile 515B. When settling window522B is within the center of the field of view of the electron beamcolumn and/or when the velocity of the stage has slowed to below athreshold value (e.g., approximately 0.0001 m/s), which may indicatethat settling window 522B is within the center of the field of view ofthe electron beam column, raster scanning of second registration area520B and the NCEM-enabled cells of second tile 515B may commence asdescribed herein. Once all of the NCEM-enabled cells of second tile 515Bare scanned or otherwise exposed to the electron beam, the stage maymove so that another tile (not shown) is positioned within the field ofview of the electron beam column. This process may continue until alltiles within a swath like swath 518 and/or a NCEM-enabled cell vehicle130 are exposed to the electron beam or scanned.

FIG. 5C provides a block diagram of an exemplary logic section 525 of anNCEM-enabled cell vehicle 130 that may be included in a tile, like tile515. Logic section 525 includes registration area 520 as well as aplurality of NCEM-enabled fill cells 530 of various widths and aplurality of product standard cells 540 of various widths. Productstandard cells 540 may be any cell filled with features used tofacilitate the operation of logic section 525 as may be defined by, forexample, a designer and/or fabricator of logic section 525. For example,product standard cells 540 may include circuits, capacitors,transistors, and so on. In some cases, a product standard cell 540 maybe a logic cell.

In FIG. 5C, the NCEM-enabled fill cells 530 are depicted as shadedcells, or regions. NCEM-enabled fill cells 530 may be placed wherever atraditional cell would otherwise be placed. However, the inventionplaces no restriction on the distribution of NCEM-enabled fill cells530. While they would typically appear in each standard cell row, theyneed not do so. Placement of NCEM-enabled fill cells 530 can be regular,semi-regular (e.g., at least one cell every X nm, or every Y cells),pseudo-random, and/or irregular/random. In some cases, two or more,NCEM-enabled fill cells 530 may be adjacent to each other. At times, oneor more of NCEM-enabled fill cells 530 may be double (or greater) heightcells. In some embodiments, a logic section like logic section 525 mayinclude both NCEM-enabled fill cells 530 and other types of cells.

FIG. 5D provides an outline of exemplary NCEM-enabled fill cells 530configured for use in connection with certain embodiments of theinvention. NCEM-enabled fill cells 530 may include certain featuresnecessary for compatibility with the logic cells, or product standardcells, that are used to form circuits on a chip. For example,NCEM-enabled fill cells 530 may include one or more test features orcircuits that may be responsive to a non-contact electronic measurementmethod such as an electron beam that may be embodied as electron beam140. An example of internal features of an NCEM-enabled fill cell 530 isprovided in FIG. 5E and discussed below.

The NCEM-enabled fill cells 530 may be configured to occupy spacebetween other (typically necessary) features of a NCEM-enabled cellvehicle such as product standard cells 540 or memory cells. NCEM-enabledfill cells 530 may be of a height that is consistent with productstandard cells in a library of product standard cells (or an integermultiple of that height) and may include power/ground rails that, forexample, extend horizontally across the cells (often, though notnecessarily, at the top and bottom of each cell).

The NCEM-enabled fill cells 530 disclosed herein may be of differentwidths; examples of which are shown in FIG. 5D. For example,NCEM-enabled fill cells 530 may be available in various widths that may,for example, be multiples of the minimum contacted poly pitch (CPP)permitted by the fabrication process for NCEM-enabled cell vehicle 130.By way of illustration and not limitation, FIG. 5D shows NCEM-enabledfill cells 530 that are 4 CPP, 13 CPP, 16 CPP, 32 CPP, and 64 CPP inwidth, but it will be appreciated that an NCEM-enabled fill cell 530 maybe any appropriate width.

FIG. 5E provides a block diagram of an exemplary NCEM-enabled fill cell530 that includes a test circuit 560 coupled to a power rail 550 and aground rail 555 via an electrically-conductive pathway 570. Exemplaryelectrically-conductive pathways 570 include but, are not limited to,metal wires, electrically conductive composite materials, and otherdeposited metal. When test circuit 560 is exposed to an electron beam140 like electron beam 140, detected electrons like detected electronsignal 145 may be produced and detected by a detector like detector 124.Analysis of the detected electron signal may determine whether testcircuit 560 is operational (e.g., correctly coupled to power rail 550and ground rail 555). Test circuit 560 may be coupled (electricallyand/or mechanically) to the substrate of the NCEM-enabled cell vehicle130.

FIG. 6 provides a flowchart illustrating an exemplary process 600 fordetermining an absolute position of a stage, such as stage 135, anabsolute position of an electron beam column such as electron beamcolumn 120, and/or a relative position between a stage and an electronbeam column. Some motion of the stage may be active, or intentional, asmay occur when the stage is moving a NCEM-enabled cell vehicle 130 aspart of, for example, an inspection process. The active motion may becontinuous or variable and is typically in the X- and/or Y-direction(s).Motion of the stage and/or electron beam may also be passive (e.g.,environmental and/or induced by operation of the stage, electron beamcolumn, and/or other equipment). Such motion may be occur in the X-, Y-and/or Z-direction(s) and may be difficult to predict. This motion maybe due to, for example, vibrations of the stage and/or hardwaresupporting the stage and/or other components of the system executingprocess 600. Process 600 may be executed by any of the systems and/orsystem components disclosed herein such as system 100.

In step 605, a first reference beam signal that may correspond to afirst reference beam like first reference beam 155R and a firstmeasurement beam signal that may correspond to a first measurement beamlike first measurement beam 155M may be received by, for example, aprocessor like server/computer/processor 110 and/or position assessmentFPGA 109 from a detector like detector like detector 116 that hasconverted the optical signals of the first reference and firstmeasurement beams into the first reference beam digital signal and firstmeasurement beam digital signal, respectively. The first reference andfirst measurement beam may be resultant from a first light beam (orother type of electro-magnetic radiation) like beam 155 that may havebeen directed toward a first beam-splitting mirror, like beam-splittingmirror 165A that is positioned between a light source as may be residentin position assessment hardware 115 and a mirror resident on the stagelike first stage mirror 150. The first light beam may be split by thefirst beam-splitting mirror into the first reference beam and the firstmeasurement beam as shown in, for example, FIGS. 1A and 1B. The firstreference beam may be directed toward a photodetector by the firstbeam-splitting mirror and may then be received by first detector. Thefirst measurement beam may be incident on the first mirror and reflectedback toward a first flat mirror like first flat mirror 166A. The firstflat mirror may then direct a portion of the first measurement beamtoward the first photodetector where it may be received and communicatedto the processor.

In step 610, a second reference beam signal that may correspond to asecond reference beam like second reference beam 160R and a secondmeasurement beam signal that may correspond to a second measurement beamlike second measurement beam 160M may be received by, for example, aprocessor like server/computer/processor 110 and/or position assessmentFPGA 109 from a detector like detector like detector 117 that hasconverted the optical signals of the first reference and firstmeasurement beams into the first reference beam signal and firstmeasurement beam signal, respectively. The second reference and secondmeasurement beam may be resultant from a second light beam (or othertype of electro-magnetic radiation) like beam 160 that may have beendirected toward a second beam-splitting mirror, like beam-splittingmirror 165B that is positioned between a light source as may be residentin position assessment hardware 115 and a mirror resident on the stagelike second stage mirror 170. The second light beam may be split by thesecond beam-splitting mirror into the second reference beam and thesecond measurement beam. The second reference beam may be directedtoward a second photodetector like second photodetector 117 by a secondflat mirror like second flat mirror 166B and may then be received by thesecond detector where it may be received and communicated to theprocessor.

Optionally, in step 615, a third reference beam signal that maycorrespond to a third reference beam like third reference beam 175R anda third measurement beam signal that may correspond to a thirdmeasurement beam like third measurement beam 175M may be received by,for example, a processor like server/computer/processor 110 and/orposition assessment FPGA 109 from a detector like detector like detector118 that has converted the optical signals of the third reference andthird measurement beams into the third reference beam digital signal andthird measurement beam digital signal, respectively. The third referenceand third measurement beam may be resultant from a third light beam (orother type of electro-magnetic radiation) like beam 175 that may havebeen directed toward a third beam-splitting mirror, like beam-splittingmirror 165C that is positioned between a light source as may be residentin position assessment hardware 115 and a mirror resident on theelectron beam column like mirror 180. The third light beam may be splitby the third beam-splitting mirror into the third reference beam and thethird measurement beam. The third reference beam may be directed towarda third photodetector like third detector 118 by the thirdbeam-splitting mirror and may then be detected by the third detector.The third measurement beam may be incident on the third mirror of theelectron beam column and reflected back toward a third flat mirror likethird flat mirror 166C which may then direct the third reflected beamtoward the third photodetector where it may be received and communicatedto the processor.

In many cases, when step 615 is performed, a fourth reference beamsignal that may correspond to a fourth reference beam like fourthreference beam 178R and a fourth measurement beam signal that maycorrespond to a fourth measurement beam like fourth measurement beam178M may be received by, for example, a processor likeserver/computer/processor 110 and/or position assessment FPGA 109 from adetector like detector like detector 119 that has converted the opticalsignals of the fourth reference and fourth measurement beams into thefourth reference beam digital signal and fourth measurement beam digitalsignal, respectively (step 620). The fourth reference and fourthmeasurement beam may be resultant from a fourth light beam (or othertype of electro-magnetic radiation) like beam 178 that may have beendirected toward a fourth beam-splitting mirror, like fourthbeam-splitting mirror 165D that is positioned between a light source asmay be resident in position assessment hardware 115 and a mirrorresident on the electron beam column like mirror 181. The fourth lightbeam may be split by the fourth beam-splitting mirror into the fourthreference beam and the fourth measurement beam. The fourth referencebeam may be directed toward a photodetector like photodetector 119 bythe fourth beam-splitting mirror and may then be received by the fourthdetector. The fourth measurement beam may be incident on the fourthmirror of the electron beam column and reflected toward a fourth flatmirror like fourth flat mirror 166D as a fourth reflected beam likefourth reflected beam 179. The fourth flat mirror may then direct thefourth reflected beam toward the fourth photodetector where it may bereceived and communicated to the processor.

Then, in step 625, an absolute position of the stage may be determinedusing, for example, the signals received in steps 605 and 610; anabsolute position of the electron beam column be determined using, forexample, the signals received in steps 615 and 620; and/or a relativeposition between the electron beam column and stage may be determinedusing the signals received in steps 605, 610, 615, and 620.

When an absolute position of the stage is determined, execution of step625 may include a comparison between the first reference beam and thefirst reflected beam to determine the difference therebetween. Oftentimes, the difference will be a difference in phase between the firstreference beam and the first reflected beam. This phase difference maybe used to determine an absolute position of the first mirror andtherefore, the stage, in a first direction (e.g., X-direction).Execution of step 625 may further include a comparison between thesecond reference beam and the second reflected beam to determine thedifference (e.g., phase difference) therebetween. This difference may beused to determine an absolute position of the second mirror andtherefore, the stage, in a second direction (e.g., Y-direction).

When an absolute position of the electron beam column is determined,execution of step 625 may include a comparison between the thirdreference beam and the third reflected beam to determine the difference(e.g., phase difference) therebetween. This difference may be used todetermine an absolute position of the third mirror and therefore,electron beam column, in a first direction (e.g., X-direction).Execution of step 625 may further include a comparison between thefourth reference beam and the fourth reflected beam to determine thedifference (e.g., phase difference) therebetween. This difference may beused to determine an absolute position of the electron beam column in asecond direction (e.g., Y-direction).

When a relative position between the electron beam column and stage isdetermined, execution of step 625 may include comparing the absoluteposition of the stage in the first and/or second directions along withthe absolute position of the electron beam in the first and/or seconddirections to determine a position of the stage relative to the electronbeam column in the first and/or second directions.

FIGS. 7A and 7B provide a flowchart illustrating an exemplary process700 for determining an absolute position of a stage, such as stage 135,an absolute position of an electron beam column such as electron beamcolumn 120, and/or a relative position between a stage and an electronbeam column. Some motion of the stage may be active, or intentional, asmay occur when the stage is moving a NCEM-enabled cell vehicle 130 aspart of, for example, an inspection process. The motion may becontinuous or variable and is typically in the X- and/or Y-direction(s).Motion of the stage and/or electron beam may also be passive (e.g.,environmental and/or induced by operation of the stage, electron beamcolumn, and/or other equipment). Such motion is typically vibrationaland may be difficult to predict. Process 700 may be executed by any ofthe systems and/or system components disclosed herein such as system200.

In step 705, a first indication of a time between emission of a firstpath length beam like first incident path length beam 210 i and receiptof a reflection of the first path length beam 210 r by, for example, aprocessor like server/computer/processor 110 and/or position assessmentFPGA 109 from, for example, position assessment hardware like positionassessment hardware 115 may be received. A path of the first path lengthbeam signal may be incident first path length beam 210 i is emitted fromposition assessment hardware, impinges on a first mirror resident on thestage like first stage mirror 150, reflects, as reflected first pathlength beam 210 r from the first mirror back to position assessmenthardware where it is detected by a detector therein.

In step 710, a path length corresponding to the first path length signalmay be determined using the first indication of the length of timebetween emission of the first path length signal and receipt of areflected first path length signal (also referred to herein as a firsttime duration) received in step 705. Step 710 may be executed by, forexample, calculating a distance traveled by the light (i.e., pathlength)by inputting the first time duration and the speed of light intoEquation 1, below.d=s*t  Equation 1

Where:

-   -   s=speed of light (299,792,458 m/s)    -   d=distance, or path length; and    -   t=time.

This distance may then be used to determine a relative and/or absoluteposition of the first mirror, and therefore the stage, in a firstdimension (e.g., the X-direction) (step 715). In some embodiments,execution of step 715 may include determining a distance the stage isfrom the position assessment hardware.

In step 720, a second indication of a time between emission of a secondpath length beam like second path length beam 215 and receipt of areflection of the second path length beam may be received by, forexample, a processor like server/computer/processor 110 and/or positionassessment FPGA 109 from, for example, position assessment hardware likeposition assessment hardware 115. A path of the second path length beamsignal may be emission of incident second path length beam 215 i fromposition assessment hardware, impingement on a second mirror resident onthe stage like second stage mirror 170, and reflection of a reflectedsecond path length beam 215 r from the second mirror back to positionassessment hardware where it is detected by a detector therein.

In step 725, a path length corresponding to the second path lengthsignal may be determined using the second indication of the length oftime between emission of the second reference path length signal andreceipt of a reflected second reference path length signal received instep 720 by, for example, inputting the second time duration and thespeed of light into Equation 1. This distance may then be used todetermine a relative and/or absolute position of the second mirror, andtherefore the stage, in a second dimension (e.g., the Y-direction) (step730). In some embodiments, execution of step 730 may include determininga distance the stage is from the position assessment hardware.

Optionally, in step 735, a third indication of a time between emissionof a third path length beam like third path length beam 220 and receiptof a reflection of the third path length beam may be received by, forexample, a processor like server/computer/processor 110 and/or positionassessment FPGA 109 from, for example, position assessment hardware likeposition assessment hardware 115. A path of the third path length beam220 may be emission of an incident third path length signal 220 i fromposition assessment hardware, impingement on a third mirror resident onan electron beam column like third mirror 180, and reflection of areflected third path length beam 220 r from the third mirror back toposition assessment hardware where it is detected by a detector therein.

Optionally, in step 740, a path length corresponding to the third pathlength signal may be determined using the third indication of the lengthof time between emission of the third reference path length signal andreceipt of a reflected third reference path length signal (also referredto herein as a third time duration) received in step 735 by, forexample, inputting the third time duration and the speed of light intoEquation 1. This distance may then be used to determine a relativeand/or absolute position of the third mirror, and therefore the electronbeam column, in a first dimension (e.g., the X-direction) (step 745). Insome embodiments, execution of step 745 may include determining adistance the stage is from the position assessment hardware.

In step 750, a fourth indication of a time between emission of a fourthpath length beam like fourth path length beam 230 and receipt of areflection of the fourth path length beam may be received by, forexample, a processor like server/computer/processor 110 and/or positionassessment FPGA 109 from, for example, position assessment hardware likeposition assessment hardware 115. A path of the fourth path length beamlike fourth path length beam 230 may be emission of an incident fourthpath length beam 230 i from position assessment hardware, impingement ona fourth mirror resident on an electron beam column like fourth mirror181, and reflection of a reflected fourth path length beam 230 r fromthe fourth mirror back to position assessment hardware where it isdetected by a detector therein.

In step 755, a path length corresponding to the fourth path lengthsignal may be determined using the fourth indication of the length oftime between emission of the fourth reference path length signal andreceipt of a reflected fourth reference path length signal received instep 750 by, for example, inputting the fourth time duration and thespeed of light into Equation 1. This distance may then be used todetermine a position of the fourth mirror, and therefore the electronbeam column, in a second dimension (e.g., the Y-direction) (step 760).In some embodiments, execution of step 760 may include determining adistance between the electron beam column and the position assessmenthardware and/or a relative distance between the electron beam column andthe position assessment hardware. Optionally, in step 765, a relativeposition between the stage and the electron beam column may bedetermined using, for example, the positions determined in steps 715,730, 745, and/or 760.

FIG. 8 provides a flowchart illustrating an exemplary process 800 fordetermining a position of a stage, like stage 135, relative to anelectron beam column, like electron beam column 120 as a NCEM-enabledcell vehicle and/or portions thereof is tested using an electron beamemanating from the electron beam column. Some motion of the stage may beintentional as may occur when the stage is moving a NCEM-enabled cellvehicle 130 as part of, for example, an inspection process. The motionmay be active and/or passive as explained herein. Process 800 may beexecuted by any of the systems and/or system components disclosed hereinsuch as system 300.

In step 805, a first indication of a first time duration extendingbetween emission of a first compound beam like first portion of firstcompound beam 310 and receipt of a reflection of the first compound beamby, for example, a processor like server/computer/processor 110 and/orposition assessment FPGA 109 from, for example, position assessmenthardware like position assessment hardware 115. An exemplary path of thefirst compound beam signal may be emission from position assessmenthardware, impingement on a first mirror resident on the stage, such asfirst stage mirror 150, reflection to a first reflection mirror likefirst reflection mirror 340 toward a second reflection mirror likesecond reflection mirror 345, reflection from the second reflectionmirror toward a third mirror positioned on an electron beam column likethird mirror 180, and reflection from the third mirror back to positionassessment hardware where it is detected by a detector therein. Anotherexemplary path of the first compound beam signal is the reverse of thepath just described.

In step 810, a path length for the first compound signal may bedetermined using the first indication of the length of time betweenemission of the first compound signal and receipt of a reflected firstcompound signal received in step 805. Step 810 may be executed by, forexample, calculating a distance traveled by the light (i.e., pathlength)by inputting the first time duration and the speed of light intoEquation 1. This distance may then be used to determine a position ofthe first mirror, and therefore the stage, relative to the third mirror,and therefore the electron beam column, in a first dimension (e.g., theX-direction) (step 815).

In step 820, a second indication of a second time duration extendingbetween emission of a second compound beam like second compound beam 320and receipt of a reflection of the second compound beam by, for example,a processor like server/computer/processor 110 and/or positionassessment FPGA 109 from, for example, position assessment hardware likeposition assessment hardware 115. An exemplary path of the secondcompound beam signal may be emission from position assessment hardware,impingement on a fourth mirror resident on the electron beam like fourthmirror 181, reflection to third reflection mirror 350, reflection towardfourth reflection mirror 355, reflection from the fourth reflectionmirror 355 toward a second mirror positioned on a stage like secondstage mirror 170, and reflection from the second mirror of the stageback to position assessment hardware where it is detected by a detectortherein.

In step 825, a path length for the second compound signal may bedetermined using the second indication of the length of time betweenemission of the second compound signal and receipt of a reflected secondcompound signal received in step 820. Step 825 may be executed by, forexample, calculating a distance traveled by the light (i.e., pathlength) by inputting the second time duration and the speed of lightinto Equation 1. This distance may then be used to determine a positionof the second mirror, and therefore the stage, relative to the fourthmirror, and therefore the electron beam column, in a second dimension(e.g., the Y-direction) (step 830).

FIGS. 9A and 9B provide a flowchart illustrating an exemplary process900 for registering a position of a tile, like tile 515, and, in someinstances, an NCEM-enabled cell vehicle like NCEM-enabled cell vehicle130 that includes the tile. Process 900 registers an actual position ofthe tile using a registration area resident within the tile. Followingregistration of the tile, one or more tests on one or more NCEM-enabledcells included within the tile may be performed when a target within thetile is exposed to a non-contact electronic measurement via, forexample, an electron beam like electron beam 140. In some cases, themeasurement may be made while the tile (via the NCEM-enabled cellvehicle it is associated with) moves on a stage, like stage 135. Themotion of the stage may be continuous along a swath, like swath 518, andthen change briefly so that, for example, an adjacent swath of tiles maybe exposed to the electron beam. For example, a stage may move so thatall tiles in a in a columnar swath oriented in the Y-direction areexposed to the electron beam. Then, when the end of the swath isreached, the stage may move in the X-direction to align an adjacentswath oriented in the Y-direction to the electron beam after which thestage may move in the Y-direction so that the tiles in the adjacentswath may be exposed to the electron beam via the continuous motion ofthe stage in the Y-direction from one side of the NCEM-enabled cellvehicle to the other. Process 900 may be performed by, for example,system 100, 200, or 300 or any component, or combination of components,thereof.

In step 905, a recipe for a NCEM-enabled cell vehicle may be received bya processor like, for example, server/computer/processor 110 from, forexample, a database like database 105. The recipe may includeinformation regarding how the NCEM-enabled cell vehicle is divided intotiles like tile 515. For example, the recipe may include a positionand/or a specification (e.g., composition, dimensions, electricalproperties, etc.) of various features of the NCEM-enabled cell vehicle.These features include, but are not limited to, a position and/orcontents of a each tile within the NCEM-enabled cell vehicle, a positionand/or contents of a registration area like registration area 520 forone or more tiles, a position and/or contents of NCEM-enabled cells likeNCEM-enabled fill cells 530, product standard cells, memory cells,and/or test cells within one or more tiles, and/or a position and/orcontents of same. For example, the recipe may indicate a characteristic,position, and/or dimension of one or more tiles and a position ofregistration area(s) and/or NCEM-enabled cell(s) in the X-, Y-, and/orZ-planes and/or a position of the one or more registration area(s)and/or NCEM-enabled cells within a subject tile relative to otherfeatures of the NCEM-enabled cell vehicle. At times, the recipe may beand/or may include a vector map of contents of the respectiveNCEM-enabled cell vehicle and/or tile. In some embodiments, the recipemay be received responsively to a query or other request generated by acomputing device like server/computer/processor 110. At times, thisquery or request may be generated responsively to receiving a requestfrom a user and/or receiving information (e.g., part number, type,manufacturing lot, etc.) regarding the NCEM-enabled cell vehicle via,for example, communication interface 125.

Optionally, one or more parameters of a system and/or device executingprocess 900 and/or used to perform an NCEM measurement and/or provideinformation to a processor executing process 900 (e.g., electron beamcolumn 120, stage 135, position assessment hardware 115, etc.) may beincluded in, and/or received with, the recipe received in step 905and/or may be known to a processor executing process 900 and/or may beused to determine an expected position for a tile. Exemplary parametersinclude, but are not limited to, a rate of motion for a stage upon whichthe NCEM-enabled cell vehicle and/or tile is positioned, a degree ofbeam drift for the electron beam column, how the stage's rate of motionmay change when approaching and/or leaving a target region, and/or howlong it takes for a stage to change direction as may occur whenbeginning to scan a new swath and/or tile. In some embodiments,information regarding the electron beam column (e.g., beam drift) mayalso be received in step 905.

In step 910, an expected, or calculated, position of a tile, aregistration area, and/or features included therein (e.g., test cells,NCEM-enabled fill cells, NCEM-enabled cells, product standard cells,and/or wires) may be determined using the received recipe, systemparameters, and/or vector data included in the recipe. The expectedposition of the tile, the registration area, and/or features includedtherein may be an absolute expected position and/or a position relativeto the electron beam column and/or stage.

Step 910 may be executed for some, or all, tiles of a NCEM-enabled cellvehicle. Often times, execution of step 910 includes determining anexpected position of a registration area. For embodiments whereparameters of a system and/or device are received and/or known,information regarding, for example, a typical rate of motion for a stagesupporting the tile that is to be exposed to an electron beam may beused to determine an expected position of a tile. Additionally, oralternatively, a known quantity of beam drift may be used to determinean expected position of a tile and/or registration area. The expectedposition of a tile and/or registration area may be an absolute expectedposition on, for example, and X and Y coordinate plane and/or a positionrelative to the electron beam column.

Optionally, in step 915, position and/or motion information for a stagelike stage 135, that the NCEM-enabled cell vehicle that includes thetile is positioned upon may be received. This information may bereceived over time (e.g., continuously, periodically, and/or as-needed)while the stage is moving during NCEM testing of the NCEM-enabled cellvehicle and/or a target therein. Position and/or motion information mayinclude, but is not limited to, a position in the X-, Y-, and/orZ-direction(s), a position of the stage relative to the electron beamcolumn, and/or a rate of motion in the X-, Y-, and/or Z-direction.

In some embodiments, the position and/or motion information of step 915may include a position for an electron beam column like electron beamcolumn 120 that directs an electron beam toward the tile in step 920. Inthese embodiments, position and/or motion information for the stage (andtherefore the NCEM-enabled cell vehicle) may be relative to a positionof the electron beam column instead of being an absolute position and/orabsolute rate of motion for the stage. In some embodiments, positionand/or movement information may include detected vibrations and/or aresonant frequency of the stage and/or electron beam column.Additionally, or alternatively, position and/or movement information mayinclude a relative difference in position between the NCEM-enabled cellvehicle and the electron beam column and/or electron beam.

Information regarding movement of the stage, and therefore movement ofan NCEM-enabled cell vehicle positioned on the stage may be determinedusing any equipment and/or process capable of detecting minute (e.g.,10-0.1 nm) movements of the stage and/or NCEM-enabled cell vehicle. Theposition information received in step 915 may be information provided byposition assessment hardware, such as position assessment hardware 115,and/or may be a position and/or rate of motion determined by a computerlike server/computer/processor 110 using information received from theposition assessment hardware. In some cases, the information received instep 915 may be light (e.g., laser) and/or radio interferometryinformation. In some instances, the information received in step 915 maybe continuously received over time to, for example, facilitatedetermination of a position of the registration area as it is movingand/or raster scanning of the registration area or other portions of theNCEM-enabled cell vehicle. In these instances, the position and/ormotion information may establish a feedback loop with a processor orcontroller (e.g., column FPGA 107) controlling the operation of anelectron beam column (e.g., electron beam column 120) so that adeflection angle of an electron beam emanating from the electron beamcolumn may be responsive to the position and/or motion informationreceived in step 915 while the registration area is scanned. In somecases, the position and/or motion information may be acquired byposition assessment hardware like position assessment hardware 115 via aprocess shown and described above with regard to FIGS. 1A, 1B, and/or4A-4C. In some embodiments, execution of step 915 is optional.

A particle beam, like electron beam 140, may then be directed toward aregion of the tile corresponding to the expected position of theregistration area for a time period sufficient to raster scan theregistration area and/or receive a response (e.g., detected electrons)of the registration area to the electron beam as the registration area(along with the rest of the NCEM-enabled cell vehicle) may move with thestage (step 920). In some embodiments, raster scanning the registrationarea may involve changing, or adjusting, a feature the electron beamand/or an deflection angle of the electron beam over time as it hits theregistration area so that the electron beam stays focused on theregistration area for a time period sufficient to raster scan theregistration area while it is moving along with the stage. For example,a deflection angle for the electron beam raster scanning theregistration area may be continuously adjusted over a period of timesufficient to fully scan the registration area as the tile including theregistration area moves along with the stage. An example of how theraster scanning and/or adjustment of the deflection angle of theelectron beam may be performed while the stage is moving is shown inFIGS. 4A-4C and is described above with regard to the discussion ofFIGS. 4A-4C.

In some embodiments, the stage may not be intentionally moving via, forexample, activation and/or operation of hardware configured to move thestage. In these embodiments, the stage may be relatively stationary butmay still be subject to vibrations or other small movements caused by,for example, environmental disturbances of the stage and/or electronbeam column. In these embodiments, position information may still bereceived and used to adjust a deflection angle of the of the beam sothat it is incident on the registration area in a manner thatfacilitates the raster scanning of the registration area.

In step 925, an indication of a response of the registration area to theelectron beam (e.g., detected electron signal like detected electronsignal 145) may be received. In some embodiments, the indication may bea result of a voltage contrast measurement of detected electrons thatwere incident on the registration area. Additionally, or alternatively,the indication may be an image like images 1101 and 1102 of FIGS. 11Aand 11B, respectively. Further details regarding images 1101 and 1102are provided below with regard to the discussion of FIGS. 11A and 11B.

The received indication may then be analyzed to determine an actualposition of the registration area and/or features within theregistration area (step 930). In some cases, execution of step 930 mayinclude determining that the registration area and by extension, thetile and/or the NCEM-enabled cell vehicle associated with theregistration area has shifted from the expected position determined instep 910 in the X-, Y-, and/or Z-directions. A difference between theexpected and actual positions of the registration area may then bedetermined and this change may be applied to other features of the tileto determine the actual position of the tile and/or NCEM-enabled cellsincluded therein (step 935).

In some embodiments, a difference between the expected and actualpositions of the registration area may be used to determine a degree ofbeam drift (i.e., a change in the deflection angle of the electron beamover time that may be a function of, for example, an operation of theelectron beam column and/or stage). In these embodiments, adetermination of beam drift may include execution of process 900 aplurality (e.g. 50, 500, 5,000, etc.) of times so that a plurality ofdifferences between the expected and actual positions of theregistration area may be determined and then used to calculate a degreeof beam drift over time. In some embodiments, the beam drift may be aparameter of the system that is received in step 905. Additionally, oralternatively, a beam drift determination via execution of process 900and/or portions thereof may incorporate and/or be used to update a knownamount of beam drift for the system that, in some instances, may bestored in database 105 and/or added to a recipe.

In some cases, the indication received in step 925 may be a detectorimage of the region of the tile corresponding to the expected positionfor the registration area determined in step 910. In these instances,execution of step 930 may include performing a comparative analysisbetween the detector image that shows the actual positions for featuresimaged by the raster scan of step 920 with the expected position (as maybe determined in step 910) of corresponding features of the registrationarea to determine whether the expected position of the features of theregistration area aligns with the actual position of the features of theraster-scanned area (i.e., the region of the tile corresponding to theexpected registration area). A result of this comparative analysis mayindicate, for example, whether the expected position of the registrationarea aligns with the raster-scanned area and/or whether the tile hasshifted from and/or is not aligned with its expected position). Anydifference between the expected and actual positions of the features ofthe registration area may be extrapolated to the remainder of the tileand/or NCEM-enabled cell vehicle in which the registration area/tileresides to determine, for example, an actual position of the tile and/orfeatures within the tile such as NCEM-enabled cells (step 935). In someinstances, there may be no difference between the expected and actualpositions of the features within the registration area. In theseinstances, the expected and actual positions of the registration areaare aligned and no further alignment and/or adjustment of a deflectionangle for the electron beam may be needed to properly expose the tileand/or features (e.g., NCEM-enabled cells) included therein to theelectron beam. This may enable the accurate targeting of the electronbeam to interact with features within the tile outside of theregistration area for testing thereof as is explained herein. In otherinstances, there may be a difference between the expected and actualpositions of the features within the registration area. In these cases,the expected and actual positions of the registration area are notaligned and, as such, an alignment and/or adjustment of a deflectionangle for the electron beam may be performed so that the electron beamis properly aligned to be incident on the target regions of the tile(e.g., NCEM-enabled cells) (step 940). This adjustment of the deflectionangle may compensate for changes in stage position and/or electron beamcolumn position that, in some cases, were previously unknown and mayenable the accurate targeting of the electron beam to interact withfeatures within the tile outside of the registration area for testingthereof as is explained further herein.

In step 945, when and where to direct the aligned electron beam toimpinge on the NCEM-enabled cells within the tile may be determined.This determination may compensate for, beam drift, stage motion, and/orother factors over a time period sufficient to expose each NCEM-enabledcell within a tile to the electron beam.

In step 950, the electron beam may then be separately and sequentiallydirected to a position corresponding to an actual position of individualNCEM-enabled cells resident in the tile for a time period sufficient totest the individual NCEM-enabled cells. The actual position of therespective individual NCEM-enabled cells may be determined using thedetermined actual position of the tile and/or NCEM-enabled cells in step935, position information received in step 915, and/or the recipereceived in step 905. In some embodiments, when the tile is positionedon a moving stage, execution of step 950 may include changing, oradjusting, a deflection angle of the electron beam over time as it hitseach individual NCEM-enabled cell so that the electron beam staysfocused on a target individual NCEM-enabled cell while it is movingalong with the stage. For example, a deflection angle for the electronbeam may be continuously adjusted over a period of time sufficient totest the individual NCEM-enabled cell as it moves along with the stage.An example of how the adjustment of the deflection angle of the electronbeam may be performed while the stage is moving is described above withregard to FIGS. 4A-4C.

In some embodiments, only the NCEM-enabled cells (as opposed to theentire tile) are exposed to the electron beam. This may increasethroughput because, for example, not all regions of a tile are exposedto the electron beam thereby saving, for example, time, processingpower, and/or energy used to operate the equipment to scan the entiretile and interpret results of this scanning. In addition, selectivelyexposing only the NCEM-enabled cells to the electron beam may preservethe operability of the product standard cells of the tile because theyare not damaged by exposure to the electron beam.

In step 955, an indication of a response of the NCEM-enabled cell to theelectron beam 140 may be received. The indication may be, for example, amagnitude of detected electron intensity, an indication of voltagecontrast and/or a count of detected electrons received as a function ofposition. In step 960, the indication may be provided to a processorand/or a display device for viewing by a user as, for example, a graphof voltage contrast and/or detected electron intensity.

In some embodiments, execution of step 910, 930, and/or 940 may includereceiving position information for a stage and/or an electron beamcolumn generating the electron beam that is directed toward thetile/registration area. The position information may be received fromposition assessment hardware like position assessment hardware 120.

FIGS. 10A and 10B provide a flowchart illustrating an exemplary process1000 for registering a position of a tile, like tile 515, and, in someinstances an NCEM-enabled cell vehicle thereof that includes the tile.Process 1000 registers the position of the tile using a registrationarea resident within the tile like registration area 520. Followingregistration of the tile, one or more tests on one or more NCEM-enabledcells included within the tile that may, in some instances, be executedas the tile (via the NCEM-enabled cell vehicle it is associated with)moves on a stage, like stage 135, and is exposed to a non-contactelectronic measurement via an electron beam like electron beam 140.Unlike with process 900, the motion of the stage may not be continuousalong a swath like swath 518 so that each tile in a swath may beindividually focused on. Stated differently, the stage may sequentiallymove the NCEM-enabled cell vehicle so that each tile may be individuallyscanned with an electron beam like electron beam 140. In this way, onceall target regions, or test sites, (e.g., NCEM-enabled cells likeNCEM-enabled fill cells 530) within a particular tile are exposed to theelectron beam, the stage may move NCEM-enabled cell vehicle so that thenext tile within a swath may be exposed the electron beam for testing.Process 1000 may be performed by, for example, system 100, 200, or 300,or any component or combination of components thereof.

In step 1005, a recipe for a NCEM-enabled cell vehicle may be receivedby a processor like, for example, server/computer/processor 110. Therecipe received in step 1005 may be similar to the recipe received instep 905 and may include information regarding how the NCEM-enabled cellvehicle thereof is divided into tiles like tile 515, a position of anexact center point of each tile like exact center point 524, and/or aposition of a settling window of each tile like settling window 522. Insome embodiments, information regarding the electron beam column (e.g.,beam drift) may also be received in step 1005.

Optionally, one or more parameters of a system and/or device executingprocess 1000 and/or used to perform an NCEM measurement and/or provideinformation to a processor executing process 1000 (e.g., electron beamcolumn 120, stage 135, position assessment hardware 115, etc.) may beincluded in the recipe received in step 1005 and/or may be known to aprocessor executing process 1000 and/or may be used to determine a sizeof a tile, a size of a swath, an expected position of an exact center ofa tile, an expected position of a settling window of a tile, and/or anexpected position for a tile. Exemplary parameters include, but are notlimited to, a rate of motion for a stage upon which the NCEM-enabledcell vehicle and/or tile is positioned, a size of an area the electronbeam can scan (this area may be used to set tile size and/ordimensions), a degree of beam drift for the electron beam column, howthe stage's rate of motion may change when approaching a target region,and/or how long it takes for a stage to change direction such as whenscan a first column is scanned in the Y-direction and moving in theX-direction to prepare to scan a second column in the Y-direction.

In step 1010, an expected, or calculated, position of a tile, aregistration area, and/or features included therein (e.g., NCEM-enabledcells, NCEM-enabled fill cells, test cells, product standard cells,and/or wires) may be determined using the received recipe, vector dataincluded in the recipe, and/or system parameters. The expected positionof the tile, the registration area, and/or features included therein maybe an absolute expected position and/or a position relative to anelectron beam column. In some embodiments, determining the expectedposition of a tile, a registration area, and/or features includedtherein may include determining a position of the exact center and/orsettling window of the tile using the recipe and/or parameters relativeto, for example, a field of view for the electron beam column.Additionally, or alternatively, determining the expected position of atile, a registration area, and/or features included therein may includedetermining a rate of speed for the stage and when the stage mayposition a tile so that the exact center and/or settling window of thetile is positioned within a field of view for the electron beam column.

Step 1010 may be executed for some or all tiles of a NCEM-enabled cellvehicle. Often times, execution of step 1010 includes determining anexpected position of a registration area. For embodiments whereparameters of a system and/or device are received and/or known,information regarding, for example, a typical rate of motion for a stagesupporting the tile that is to be exposed to an electron beam may beused to determine an expected position of a tile. Additionally, oralternatively, a known quantity of beam drift and/or stage velocity maybe used to determine an expected position of the tile and/orregistration area that may be an absolute expected position and/or aposition relative to an electron beam column and/or may be used toperform step 1020 while the stage is moving.

In step 1015, position and/or motion information fora stage (e.g., stage135) that the NCEM-enabled cell vehicle that includes the tile ispositioned upon may be received. This information may be received overtime while the stage is moving during NCEM testing of the NCEM-enabledcell vehicle. Position and/or motion information may include, but is notlimited to, a position in the X-, Y-, and/or Z-direction and/or a rateof motion in the X-, Y-, and/or Z-direction. In some embodiments, theposition information for the stage (e.g., absolute position of the stageand/or position of the stage relative to the electron beam column) maybe received over time so that an absolute and/or relative velocity ofthe stage may be determined over time. The received position informationmay be a result of execution of process 600, 700, and/or 800 asdiscussed above with regard to FIGS. 6, 7, and 8 respectively.

In some embodiments, the position and/or motion information of step 1015may include a position for an electron beam column like electron beamcolumn 120 that directs an electron beam toward the tile in step 1025.In these embodiments, position and/or motion information for the stage(and therefore the NCEM-enabled cell vehicle) may be relative to aposition of the electron beam column instead of being an absoluteposition and/or absolute rate of motion for the stage. In someembodiments, position and/or movement information may include detectedvibrations and/or a resonant frequency of the stage and/or electron beamcolumn. Additionally, or alternatively, position and/or movementinformation may include a relative difference in position between theNCEM-enabled cell vehicle and the electron beam column and/or electronbeam.

In step 820, it may be determined whether a velocity of the stage isbelow a certain threshold (as may be the case when the stage slows downas the settling window approaches a center of the field of view for theelectron beam column) and/or if a position of the tile is such that thesettling window or exact center is in the correct position to beginraster scanning a registration area of the tile (i.e., at, or near, acenter of a field of view of the electron beam column). In manyembodiments, the stage may move quickly between tiles until the exactcenter of the tile is within a certain range of the center of the fieldof view of the electron beam column after which the stage may slow downso that the exact center of the tile may be precisely positioned toalign with the center of the field of view of the electron beam column.When the velocity of the stage decreases, this may be an indication thatthe exact center like 524 of the tile is within a settling window likesettling window 522 of the field of view of the electron beam column.When the velocity of the stage is not below a certain threshold and/orif a position of the tile is such that the settling window or exactcenter is not in the correct position (e.g., sufficiently close to thecenter of the field of view for the electron beam column) to beginraster scanning a registration area of the tile, step 1015 may berepeated.

When the velocity of the stage is below a certain threshold and/or if aposition of the tile is such that the settling window or exact center ofthe tile is in the correct position (e.g., sufficiently close to acenter of a point of view of the electron beam column), an instructionto raster scan a region of the tile corresponding to the expectedposition of the registration area with an electron beam like electronbeam 140 for a time period sufficient to raster scan the region and/orreceive a response (e.g., detected electrons) of the region to theelectron beam may be provided to the electron beam column (step 1025).

In some embodiments, raster scanning the region of the tilecorresponding to the expected position of the registration area mayinvolve changing, or adjusting, a feature the electron beam and/or andeflection angle of the electron beam over time so that the electronbeam stays focused on the region of the tile corresponding to theexpected position of the registration area while it is slowing down tobring a center of the tile into the electron beam column's point of viewand/or increasing in speed as the tile goes from a complete stop (ornearly complete stop) to begin moving to the next tile to be exposed tothe electron beam (e.g., the next tile in a swath). For example, adeflection angle for the electron beam raster scanning the registrationarea may be continuously adjusted over a period of time sufficient tofully scan the registration area as the tile including the registrationarea moves along with the stage and/or is subject to vibration. Thiscontinuous adjustment may be made using the position informationreceived in step 1015. An example of how the raster scanning and/oradjustment of the deflection angle of the electron beam may be performedwhile the stage is moving is shown in FIGS. 4A-4C and is described abovewith regard to the discussion of FIGS. 4A-4C. When the stage is notintentionally, or actively, moving, the raster scan may be performed ina typical manner by scanning along the registration area in the X-and/or Y-directions until the entirety of the registration area has beenscanned. However, even when the stage is not actively moving, the stageand/or the electron beam column may still be subject to vibrations orother movement that may be accounted for and/or incorporated into aninstruction to raster scan the region of the tile corresponding to theexpected position of the registration area using continuously receivedposition information.

In some instances, the stage may not be intentionally moving via, forexample, activation and/or operation of hardware configured to move thestage. In these embodiments, the stage may be relatively stationary butmay still be subject to vibrations or other small movements caused by,for example, environmental disturbances of the stage and/or electronbeam column. In these instances, position information may still bereceived and used to adjust a deflection angle of the of the beam sothat it is incident on the registration area in a manner thatfacilitates the raster scanning of the registration area thatcompensates for passive movement of the stage and/or electron beamcolumn.

In step 1030, an indication of a response of the registration area tothe electron beam (e.g., a detected electron signal like detectedelectron signal 145) may be received. In some embodiments, theindication may be a voltage contrast measurement of detected electronsthat were incident on the registration area. Additionally, oralternatively, the indication may be an image like images 1001 and 1002of FIGS. 10A and 10B, respectively. Further details regarding images1001 and 1002 are provided below with regard to the discussion of FIGS.10A and 10B. In some embodiments, the indication received in step 1030may be similar to the indication received in step 925.

The received indication may then be analyzed to determine an actualposition of the registration area and/or features within theregistration area (step 1035). In some cases, execution of step 1035 mayinclude determining that the registration area and by extension, thetile and/or NCEM-enabled cell vehicle associated with the registrationarea has shifted from the expected position determined in step 1010 inthe X-, Y-, and/or Z-directions. A difference between the expected andactual positions of the registration area may then be determined andthis difference may be applied to other features of the tile todetermine the actual position of the tile and/or NCEM-enabled cellsincluded therein (step 1040). In some cases, execution of steps 1035and/or 1040 may be similar to execution of steps 930 and/or 935,respectively.

In some embodiments, a difference between the expected and actualpositions of the registration area may be used to determine a degree ofbeam drift (i.e., a change in the deflection angle of the electron beamover time that may be a function of, for example, an operation of theelectron beam column and/or stage). In these embodiments, adetermination of beam drift may include execution of process 1000 aplurality (e.g. 50, 500, 5,000, etc.) of times so that a plurality ofdifferences between the expected and actual positions of theregistration area may be determined and then used to calculate a degreeof beam drift over time. In some embodiments, the beam drift may be aparameter of the system that is received in step 1005. Additionally, oralternatively, a beam drift determination via execution of process 1000and/or portions thereof may incorporate and/or be used to update a knownamount of beam drift for the system.

In some cases, the indication received in step 1030 may be a detectorimage (like images 1101 and/or 1102) of the region of the tilecorresponding to the expected position for the registration areadetermined in step 1010. In these instances, execution of step 1035 mayinclude performing a comparative analysis between the detector imageand/or positions for features imaged therein received in step 1030 withthe expected position (as may be determined in step 1010) of features ofthe registration area and their respective expected positions todetermine whether the expected position of the features of theregistration area aligns with the actual position of the features of theimaged/raster-scanned area (i.e., whether the registration area alignswith and/or has shifted from its expected position). Any differencebetween the expected and actual positions of the features of theregistration area may be extrapolated to the remainder of the tileand/or NCEM-enabled cell vehicle in which the registration area/tileresides to determine, for example, an actual position of the tile and/orfeatures within the tile such as NCEM-enabled cells (step 1040). In someinstances, there may be no difference between the expected position ofthe features within the registration area and the actual position of thefeatures within the registration area. In these instances, the expectedand actual positions of the registration area are aligned and no furtheralignment and/or adjustment of a deflection angle for the electron beammay be needed to properly expose the tile and/or features (e.g.,NCEM-enabled cells) included therein to the electron beam. This mayenable the accurate targeting of the electron beam to interact withfeatures within the tile outside of the registration area for testingthereof as is explained further with regard to step 1055, below. Inother instances, there may be a difference between the expected positionof the features within the registration area and the actual position ofthe features within the registration area. In these cases, the expectedand actual positions of the registration area are not aligned and, assuch, an alignment and/or adjustment of a deflection angle for theelectron beam may be performed so that the electron beam is incident onthe target regions of the tile (e.g., NCEM-enabled cells) (step 1045).This adjustment of the deflection angle may compensate for changes instage position and/or electron beam column position that may have beenpreviously unknown and may enable the accurate targeting of the electronbeam to interact with features within the tile outside of theregistration area for testing thereof as is explained further withregard to step 1055, below.

In step 1050, when and where to direct the aligned electron beam toimpinge on the NCEM-enabled cells within the tile may be determined.This determination may compensate for the stage motion over a timeperiod sufficient to expose each NCEM-enabled test cell within a tile tothe electron beam.

In step 1055, the electron beam may then be separately and sequentiallydirected to a position corresponding to an actual position of individualNCEM-enabled cells resident in the tile for a time period sufficient totest the individual NCEM-enabled cells. The actual position of therespective individual NCEM-enabled cells may be determined using thedetermined actual position of the tile and/or NCEM-enabled cells in step1035 and/or the recipe received in step 1005. In some embodiments, whenthe tile is positioned on a moving stage, execution of step 1050 mayinclude changing, or adjusting, a deflection angle of the electron beamover time as it hits each individual NCEM-enabled cell so that theelectron beam stays focused on a target individual NCEM-enabled cellwhile it is moving along with the stage. For example, a deflection anglefor the electron beam may be continuously adjusted over a period of timesufficient to test the individual NCEM-enabled cell as it moves alongwith the stage. An example of how the adjustment of the deflection angleof the electron beam may be performed while the stage is moving isdescribed above with regard to FIGS. 4A-4C.

In some embodiments, only the NCEM-enabled cells are exposed to theelectron beam. This may increase throughput because, for example, notall regions of a tile are exposed to the electron beam thereby saving,for example, time, processing power, and/or energy used to operate theequipment. In addition, selectively exposing only the NCEM-enabled cellsto the electron beam may preserve the operability of the productstandard cells of the tile because they are not damaged by exposure tothe electron beam.

In step 1060, an indication of a response of the NCEM-enabled cell tothe electron beam may be received. The indication may be, for example, amagnitude of detected electron intensity, an indication of voltagecontrast and/or a count of detected electrons received as a function ofposition. In step 1065, the indication may be provided to a processorand/or a display device for viewing by a user as, for example, a graphof voltage contrast, pixel energy level, and/or detected electronintensity.

In some embodiments, execution of step 1010, 1030, and/or 1040 mayinclude receiving position information for a stage and/or an electronbeam column generating the electron beam that is directed toward thetile/registration area. The position information may be received fromposition assessment hardware like position assessment hardware 120.

FIGS. 11A and 11B provide exemplary images 1101 and 1102, respectively,of a region of a tile corresponding to an expected position for aregistration area like registration area 520 that may be received inand/or generated via, for example, execution of step 925 and/or 1030using an expected position of the registration area determined in step910 and/or 1010. More specifically, FIG. 11A provides a first image 1101of a region of a tile where the expected and actual positions of theregistration area align with one another. The registration area isapproximately 400 nm×400 nm square and image 1101 is shown with a grid(shown in white dotted lines) superimposed thereon showing displacementvalues for the expected position of the registration area along theX-axis and Y-axis. Image 1101 shows a plurality of regions of interest1110 (labeled 1110A-1110J) included within the imaged area that areshown by way of example and not limitation. In one example, a positionof a left side, a right side, a center, and/or an area between ofregion(s) of interest 1110A, 1110B, 1110C, 1110D, 1110E, 1110I, and/or1110J may be used to determine an actual position of the registrationarea and/or a magnitude of a shift of the region(s) of interest and/orregistration area along the X-axis. Additionally, or alternatively, aposition of a top, a bottom, a center, and/or an area between ofregion(s) of interest 1110F, 1110G, 1110H, 1110I, and/or 1110J may beused to determine an actual position of the registration area and/or amagnitude of a shift of the region(s) of interest and/or registrationarea along the Y-axis. Additionally, or alternatively, a distancebetween two or more regions of interest 1110 may be used to determine anactual position and/or a magnitude of a shift of the registration areaalong the X- and/or Y-axis. An actual position of one or more regions ofinterest 1110A-1110J may then be compared to an expected position of therespective one or more regions of interest 1110A-1110J to determine ifthe actual position of the region of interest (and therefore theregistration area) is aligned along the X-axis and/or Y-axis with theexpected position of the respective region of interest/registrationarea. In the example of image 1101, a position of regions of interest1110A-1110J shown in image 1101 is the same as the expected positionsfor the respective regions of interest 1110A-1110J. Therefore, it may bedetermined that the expected and actual positions of the registrationarea of image 1101 align with one another and, based on this finding, noalignment of the electron beam in step 945 and/or 1050 may be necessary.

FIG. 11B provides a second image 1102 of a region of a tilecorresponding to an expected position of the registration area where theexpected and actual positions of the registration area do not align withone another. The registration area of image 1101 is approximately 400nm×400 nm square and image 1102 is shown with a grid (shown in whitedotted lines) superimposed thereon showing displacement values for theexpected position of the registration area along the X-axis and Y-axis.

Image 1102 shows the plurality of regions of interest 1110A-1110Jincluded within the imaged area that are shown by way of example and notlimitation. Regions of interest 1110A-1110J of image 1102 are the sameas 1110A-1110J of image 1101 however, their position within the image isdifferent because positions of regions of interest 1110A-1110H shown inimage 1102 have shifted along the X- and Y-axis relative to thepositions of regions of interest 1110A-1110H shown in image 1101. Thus,expected position and actual position of the registration area are notthe same. More specifically, a position of regions of interest1110A-1110H has shifted approximately −50 nm along the X-axis and −50 nmalong the Y-axis. Therefore, it may be determined that the actualposition of the registration area is different from the expectedposition of the registration area by approximately 50 nm to the leftalong the X-axis and approximately 50 nm down along the Y-axis. Thisshift may be extrapolated to the position of the tile and contentsincluded therein and a direction of transmission and/or deflection angleof an electron beam used to test one or more of the regions of interest1110A-1110J may be adjusted so that it strikes the actual position (asopposed to the inaccurate expected position) of targets like target 185within the tile.

A determination of how much a registration area 520 has shifted alongthe X- and/or Y-axis may be made by, for example, comparing an image ofan expected position for the registration area (in other words, wherethe registration area should be) with an image of a region of the tilecorresponding to where the registration area should be. Additionally, oralternatively, the determination of how much a registration area 520 hasshifted along the X- and/or Y-axis may be made by, for example,comparing an image of the actual position for the registration area witha recipe of, for example, the registration area, tile, or wafer todetermine differences therebetween.

In some embodiments, a determined shift of a registration area 520 inthe X- and/or Y-direction(s) may be extrapolated to an entire tile inwhich registration area 520 is resident and, in some instances, to aregion of a NCEM-enabled cell vehicle outside the boundaries of thetile.

In some embodiments, multiple determinations of an actual position of aplurality of regions of interest 1110 may be made and then analyzed toarrive at a statistically robust determination of an overall shift of aregistration area. For example, a comparison between an expected and anactual position of 1110A, 1110B, 1110C, 1110D, 1110E, 1110F, 1110G,1110H, 1110I, and/or 1110J may be made and some of the comparisons maybe averaged to arrive at an average magnitude of shift for registrationarea 520. Additionally, or alternatively, a median or mode value for thecomparisons may be determined. In some instances, a mathematical modelmay incorporate using the comparisons.

FIG. 12A provides a block diagram of an exemplary wafer 1200 that may bean NCEM-enabled cell vehicle that includes a plurality of dies 1205 (notall of which are labeled) arranged in a grid that has coordinates alongthe Y-axis labeled with letters from A-R that represent 18 sequential(from top to bottom) rows of dies present on wafer 1200 and coordinatesalong the Y-axis labeled with numbers from 1-18 that represent 18sequential (from left to right) columns of dies 1205 present on wafer1200. Each die 1205 of wafer 1200 may be identified by its row andcolumn coordinates. For example, dies A9 and A10 are the only dies inthe first row (row A) and die B6 is the first die in the second row (rowB) of wafer 1200. In some embodiments, each die 1205 on wafer 1200 isidentical. Alternatively, there may be two or more different groups, orarrays, of dies 1205 wherein dies 1205 within the group/array areidentical to one another (within the group/array) but the dies of thedifferent groups/arrays on the same wafer may not be identical to oneanother. Stated differently, a wafer 1200 may include, for example, twoarrays of dies 1205; and dies 1205 of the first group may be differentfrom the dies 1205 of the second group.

FIG. 12B provides an exemplary array 1201 of dies 1205 that are presenton wafer 1200. The dies 1205 of array 1201 correspond to dies H7, H8,H9, H10, I7, I8, I9, and I10 of wafer 1200. Each die 1205 of array 1201should identical to each other. However, in order to test if this istrue, a target region 1210 is selected for each die 1205 for testing todetermine if the target regions 1210 for each die 1205 respond to thetest in the same way. Each target region 1210 corresponds to the samefeatures within each die 1205 and will be in the same position for eachdie 1205 so that test results from each target region 1210 (andtherefore die 1205) may be compared with one another. In someembodiments, target region 1210 may be an NECM-enabled cell, anNCEM-enabled fill cell, a product standard cell, and/or a DUT asdiscussed herein. Additionally, or alternatively, a target region 1210may be a plurality (e.g., 3, 4, 5, etc.) of regions, points, and/or orcells of a die 1205 that are the same (i.e., repeated) for each die1205. The target region 1210 for each die 1205 may then be tested via,for example, exposure to an electron beam like electron beam 140 todetermine a reaction (e.g., emitted electrons) of each target region1210 to the particle beam. These reactions may then be compared with oneanother to determine if there are one or more outlying reactions thatmay indicate a defect in a target region 1210 and/or die 1205. Furtherdetails regarding this process are provided below with regard to FIGS.11A and 11B.

The arrangement of array 1201 shown in FIG. 12B is only one example ofhow an array of dies may be arranged and/or situated for testing. Insome cases, an array of dies 1205 may include every other die 1205 in arow and/or column to form a checkerboard-like array 1201 or pattern.Alternatively, an array 1201 may be every other row or column of dies1205 or along a diagonal line. Alternatively, an array 1201 may be anyshape (e.g., square, triangle, circle) or size wafer 1200 canaccommodate.

Although array 1201 of FIG. 12B refers to dies 1205 smaller, an arraymay comprise smaller, repeatable portions of a die (e.g., a chip or acell) that may be tested in a manner similar to the testing of die 1205.Additionally, or alternatively, although only one target region 1210 isshown for each die 1205, this need not always be the case because a die1205 may have a plurality (e.g., 3, 5, 9, 20, 40, etc.) of targetregions 1210.

FIG. 13 provides a flowchart illustrating a process 1300 for performinga comparative analysis of different NCEM-enabled cell vehicles orportions (e.g., tiles) thereof. In some embodiments, process 1300 may beexecuted for the purpose of error detection. Process 1300 may beperformed by, for example, system 100, 200, 300, or any component, orcombination of components, thereof.

In step 1305, a recipe for a NCEM-enabled cell vehicle may be receivedby, for example, a computer or processor like server/computer/processor110. In some embodiments, the recipe may be for a wafer like wafer 1200.The recipe may include, for example, descriptions and/or positions offeatures (e.g., product standard cells, NCEM-enabled cells, and/or DUTs)included in the wafer, die, and/or chip. In some embodiments, executionof step 1305 may be similar to execution of step 905.

In step 1310, a plurality of target regions of interest on theNCEM-enabled cell vehicle like target region 1210 may be identifiedand/or received. Exemplary target positions may correspond to, forexample, a DUT, a product standard cell like product standard cells 340,and/or NCEM-enabled fill cells like NCEM-enabled fill cells 530. Oftentimes, a type, recipe, and/or layout of components within a targetregion for each portion of a NCEM-enabled cell vehicle is the same sothat the target regions of different portions of the NCEM-enabled cellvehicle may be compared with one another. In some cases, theidentification and/or determination of a target region may be performedusing the recipe received in step 1305.

In step 1315, a position (e.g., X and Y coordinates) for each targetregion of step 1310 may be determined using, for example, the recipe. Insome embodiments, the determination of a position for each target regionof step 1315 may incorporate execution of a portion of process 900 sothat an actual position of the NCEM-enabled cell vehicle and/or targetregion may be determined. This may assist with achieving properalignment between a target region and an electron beam during executionof step 1325, discussed below.

Optionally, in step 1320, position and/or motion information for a stagelike stage 135, on which the NCEM-enabled cell vehicle is positionedupon may be received. In some embodiments, execution of step 1320 mayresemble execution of step 915, described above.

In step 1325, an electron beam, like electron beam 140, may be directed,in some cases sequentially directed, toward each target region for atime period sufficient to test the target region using, for example, avoltage contrast measurement. Often times, step 1325 may be executed sothat target regions of different target regions of the NCEM-enabled cellvehicle are sequentially exposed to the target beam. In someembodiments, execution of step 1325 may bear similarities to theexecution of step 920. An indication of a response of each target regionto the electron beam may then be received (step 1330). Exemplaryresponses include, but are not limited to, a voltage contrastmeasurement, a detected electron count, and/or a grey level. In someinstances, the indications received in step 1330 may be referred to as aplurality of indications.

In step 1335, the indications from the target regions of differentcells, chips, or dies may be processed so that they may be compared withone another to determine differences therebetween (step 1340). Exemplarydifferences include, but are not limited to, outlying amplitude and/orfrequency fluctuations, a high level of noise, and an outlyingY-intercept value. In step 1345, an indication of the response and/or aresult of the processing and/or comparison may be provided to aprocessor like server/computer/processor 110 and/or a display device as,for example, one or more numerical values, one or more graphs, and/orone or more graphics.

In some cases, the processing of step 1335 may include calculating amean and/or a median value for each of the plurality of indications. Insome embodiments, these values may be provided to a processor and/ordisplay device as, for example, numerical values in a table and/ordisplayed on a graph so that the processor and/or a user may perform thecomparison and potentially find one or more outlying values, which maycorrespond with a target region that is defective and/or is otherwisedifferent from a processed value for a majority of target regions.

Additionally, or alternatively, the processing of step 1335 may includecomparing a phase of a signal for the plurality of indications todetermine if one or more indications is out of phase, or phase shifted,when compared with the indications for the phases for the signalscorresponding to the remaining target regions. Additionally, oralternatively, the processing of step 1335 may include comparing anamplitude for the indications to determine if an amplitude of one ormore indications is higher or lower than the majority of amplitudes forthe plurality of indications. Additionally, or alternatively, theprocessing of step 1335 may include comparing a frequency of a signal ofthe indications to determine if one or more indications have a frequencythat is different from (e.g., faster or slower) than the majority offrequencies.

Additionally, or alternatively, the processing of step 1335 may includeapplication of statistical techniques (e.g., linear regression, curvefitting, etc.) and/or mathematical modeling to the indications todetermine if there are any outlying indications including, but notlimited to, outlying amplitude and/or frequency fluctuations, a highlevel of noise, and/or an outlying Y-intercept value.

In some cases, the processing of step 1335 may include the generation ofa scatter plot that graphs a value of the indication (e.g., a grey levelor detected electron count) for each target region as a function ofpixel number, time, and/or position. FIG. 14 provides an exemplary graph1400 of pixel grey count for a plurality of target regions as a functionof pixel number that shows a scatter plot of an indication for each ofthe plurality of target regions. In this example, the indications shownon graph 1400 correspond to array 1201 of target regions 1201 H7, H8,H9, H10 and I7, I8, I9, and I10 as explained and shown above with regardto FIG. 12B. The pixel number of the X-axis of graph 1400 corresponds toparticular position, or pixel, within the target and pixel countincreases from 0-70 as the electron beam is directed to different pixels(often sequentially arranged pixels) of the target region. In someinstances, each pixel count may correspond to a length of time (e.g.,5-0.05 microseconds) that the electron beam is incident on each pixel,or sequentially placed location, of the target. In these instances, aduration of time the electron beam is incident on each pixel of thetarget is typically uniform (i.e., the same duration).

As may be seen in graph 1400, the scatter plots representing indicationsfor target regions dies H8, H9, H10 and I7, I8, I9, and I10 are groupedtogether and, in some cases, nearly overlap into a group of scatterplots 1410. Group of scatter plots 1410 has a pixel grey level in therange of approximately 2200-2400 as a function of pixel count. However,there is one outlier scatter plot 1415 that corresponds to die H7 whosegrey level is considerably higher (between approximately 2600 and 2750)as a function of pixel count than the scatter plots included in group ofscatter plots 1410. Thus, values for scatter plot 1415 are outliers whencompared with the scatter plots of the other dies/target regions and ispossible that the outlying nature depicted by scatter plot 1415represents a defective target region within die H7. This may indicatethat die H7 may be defective. In some cases, a target region associatedwith scatter plot 1415 (i.e., die H7) may be flagged for further followup and/or analysis. Additionally, or alternatively, die H7 may beflagged as damaged, defective, or otherwise as an outlier.

Thus, systems, devices, and methods for performing a non-contactelectrical measurement (NCEM) on a NCEM-enabled cell included in aNCEM-enabled cell vehicle have been herein described.

We claim:
 1. A method comprising: receiving a recipe for a die includedin a wafer, the die being divided into a plurality of tiles, each tileincluding a registration area and a plurality of non-contact electronicmeasurement (NCEM)-enabled cells, the recipe including a position forthe die within the wafer, a position of the registration area, and aposition for each of the NCEM-enabled cell of the plurality ofNCEM-enabled cells; determining an expected position of a registrationarea included in a tile of the plurality of tiles using the recipe;instructing an electron beam column to raster scan a region of the tilecorresponding to the expected position of the registration area using anelectron beam; receiving an image of the region of the tilecorresponding to the expected position of the registration area that hasbeen raster scanned; determining an actual position of the registrationarea using the image; aligning the electron beam using the actualposition of the registration area; sequentially directing the alignedelectron beam toward each of NCEM-enabled cells of the plurality ofNCEM-enabled cells within the tile of the plurality of tiles; receivinga response of each of the NCEM-enabled cells to the aligned electronbeam; and providing an indication of the response to a processor.
 2. Themethod of claim 1, wherein the tile is a first tile, the registrationarea is a first registration area, the region of the tile correspondingto the expected position of the first registration area is a firstregion of the tile corresponding to the expected position of the firstregistration area, and the plurality of NCEM-enabled cells is a firstplurality of NCEM-enabled cells, the method further comprising:determining an expected position of a second registration area includedin a second tile of the plurality of tiles; instructing an electron beamcolumn to raster scan a second region of the tile corresponding to theexpected position of the second registration area using an electronbeam; receiving an image of the second region of the tile correspondingto the expected position of the second registration area that has beenraster scanned; determining an actual position of the secondregistration area using the image; aligning the electron beam using theactual position of the second registration area; sequentially directingthe aligned electron beam toward each of NCEM-enabled cells of a secondplurality of NCEM-enabled cells within the second tile; receiving aresponse of each of the NCEM-enabled cells included in the secondplurality of NCEM-enabled cells to the aligned electron beam; andproviding an indication of the response to a processor.
 3. The method ofclaim 2, further comprising: determining a first difference between theexpected and actual position of the first registration area; determininga second difference between the expected and actual position of thesecond registration area; determining an amount of electron beam driftof the electron beam using the first and second differences; and usingthe amount of electron beam drift to align the electron beam when it isdirected toward at least one of a third registration area in a thirdtile and an NCEM-enabled cell included in the third tile.
 4. The methodof claim 1, wherein the wafer is positioned on a stage that moves whilethe electron beam is directed toward the registration area, the methodfurther comprising: receiving position information for the stage as itmoves; and adjusting a deflection angle of the electron beam on theregistration area while raster scanning the registration area, theadjustment being responsive to the position information for the stage sothat the raster scan of the registration area compensates for movementof the stage.
 5. The method of claim 4, wherein the position informationis received from at least one of an interferometer and an opticalencoder.
 6. The method of claim 1, further comprising: receivingposition information for the stage; receiving position information foran electron beam column that generates the electron beam; determining aposition of the stage relative to the electron beam column; andadjusting a deflection angle of the electron beam on the registrationarea while raster scanning the registration area responsively to therelative position between the stage and the electron beam column.
 7. Themethod of claim 1, wherein the wafer is positioned on a moving stage,the method further comprising: receiving position information for thestage over a time interval; receiving position information for anelectron beam column that generates the electron beam over the timeinterval; determining, a plurality of times, a position of the stage andrelative to the electron beam column over the time interval; andadjusting a deflection angle of the electron beam on the registrationarea over the time interval while raster scanning the registration area,the adjustment being responsive to the relative position between thestage and the electron beam column over the time interval so that theraster scan of the registration area may be compensate for the movementof the stage.
 8. The method of claim 7, further comprising: determiningan amount of column drift wherein the relative position.
 9. The methodof claim 7, wherein the position information is received from at leastone of an interferometer and an optical encoder.
 10. The method of claim1, wherein the registration area includes a plurality of features anddetermining the expected position of the registration area comprisesdetermining an expected position for two or more of the plurality offeatures and determining the actual position of the registration areacomprises determining an actual position for the two or more features ofthe plurality of features using the image, the method furthercomprising: comparing the expected and actual position for each of thetwo or more features to determine a difference therebetween, wherein thealigning of the electron beam is responsive to the difference.
 11. Themethod of claim 1, wherein tile size is responsive to at least one of apath length for the electron beam column and a size of a field of viewof the electron beam column.
 12. The method of claim 1, wherein theindication of the response of the NCEM-enabled cell to the alignedelectron beam is a voltage contrast measurement.
 13. The method of claim1, wherein the indication of the response of the NCEM-enabled cell tothe aligned electron beam is a detector current that indicates a measureof detected electron intensity.
 14. The method of claim 13, furthercomprising; converting the detector current into a grey level.
 15. Amethod comprising: receiving a recipe for a die included in a wafer, thedie being divided into a plurality of tiles, each tile having an exactcenter point and a settling window and including a registration area anda plurality of non-contact electronic measurement (NCEM)-enabled cells,the recipe including a position for the die within the wafer, a positionof the registration area, and a position for each of the NCEM-enabledcell of the plurality of NCEM-enabled cells; determining an expectedposition of a registration area included in a tile of the plurality oftiles using the recipe; receiving position information for the tile;determining whether at least one of the settling window and the exactcenter point is centered within a field of view of an electron beamcolumn and, if so, instructing an electron beam column to raster scan aregion of the tile corresponding to the expected position of theregistration area using an electron beam; receiving an image of theregion of the tile corresponding to the expected position of theregistration area that has been raster scanned; determining an actualposition of the registration area using the image; aligning the electronbeam using the actual position of the registration area; sequentiallydirecting the aligned electron beam toward each of NCEM-enabled cells ofthe plurality of NCEM-enabled cells within the tile of the plurality oftiles; receiving a response of each of the NCEM-enabled cells to thealigned electron beam; and providing an indication of the response to aprocessor.